Category Archives: 700R4/4L60/4L60E Transmission

700R4/4L60 Valve Body Overview

When is comes to this area of this line of transmissions, it is real difficult to nail it down. i have literally three different manuals open on my desk here and a catalog of footnotes i have gathered from builds i have done and advise i have gotten. so at best, this is an overview to give you an idea what to expect.

there are two major groups of valve bodies on this line of transmissions. what most people call a type 1:which is 1982-early 1987, and type 2: which is mid 87-92……often called an auxillary valve body tranny.  they are both a cast iron valve body similar to the older th350’s and 400’s.  there are 13 valve passages in the body. one being your manual valve, another being your TV, or throttle valve(which controls shift point like a vacuum modulator), and one passage believe it or not is is usually rendered useless on most transmissions for non-electric TCC engagement. there are then 3 primary shift valve passages for your main shift points. the 1-2,2-3, and 3-4 shift valves. these three valves receive oil signal from your governor and TV valve to trigger shift at the appropriate pressure signal. this leaves 7 more valve passages. these valves control downshift and accumulator characteristics and work in conjuction with the other 5 or 6 valves.

basically, during a standard rebuild, most people clean out the valve body with solvent then use a small screwdriver to make sure the springs on all the valves are not broken and the valves move freely. if there was a problem with the quality of shift at all with your transmission, you should buy the shift kit and follow the instructions. i have found that the primary source of wear in these things is the spacer plate/accumulator and not the valve body specifically. all of these trannys are prone for spacer plate wear to the point the check balls get stuck in the spacer plate. the accumulator also comes apart and beats the shit outta the plate as well.

Type 1 trannys use a fairly common midplate from what i can gather, differences being between diesel and gas models. most had 6 check balls in the case-one of em being larger than the other 5  for the TV exhaust port, and one for the accumulator housing.  there were also usually 3 check balls in the valve body on the opposite side of the spacer plate making a total of  8 check ball locations.

here you can see ach the type 1 installed on a unit. the upper left hand corner is you accumulator housing. this housing holds the 1-2 accumulator. below this accumulator under the mid plate is also your 3-4 accumulator piston. most early type set ups use a piston with a teflon seal. later type 2 set ups often used a different style piston with a rubber seal(which is considered more desirable and can be interchanged). the accumulator springs are also color coded for different tensions and shift characteristics. my transtar book list 7-9 different colors/springs here. from what i can gather black springs are thought to be the weakest and white the stiffest. the stiffer the spring the more aggressive the shift. red color being above average and blue color being just under that.  often these springs will have damage or be busted. also note that next to the accumulator is a flat plate…..similar to what a non-lockup th350 has to the front of the valve body. this is the location of the auxillary valve body on type 2 valve bodies.

type 2 valve bodies, also called auxillary valve bodies, are slightly more complex than the older trannys. the valve body is similar to the type one but is different. interchanging early and late model valve bodies is NOT recommended. also between 87 and 92/early 93 there were literally dozens of different style mid plates. there is even an interchange chart in the later model ATSG manual that at a glance…….seems like about 50 different plates! also the check ball locations change. the one later model i did for myself omitted two check balls over the type 1 i did. valve body gaskets are also different between the two valve bodies. TAKE NOTE OF WHICH GASKETS YOU HAVE DURING DISASSEMBLY! most kits come with 4-6 different gaskets. make sure you get the right ones or you will be in deep shit. gaskets are usually marked “C” for the case side of the mid plate and “V” for the valve body side, or lower valve body gasket.  one set will have a hollow pie wedge out of a spot on the edge representing the “V”, whereas the other type gasket will have a more distict “V” shape. which one goes where? well, take note during disassembly.

the Type 2 auxillary valve bodyt is located here, and has a tube that runs to the top of it from the front of the transmission. it bolts on in place of the rear cover plate location. GM started having trouble with a harsh engagement when shifting into drive or overdrive on some 700R4 models, which over a period of time not only irritated the customer but tore up the forward clutch of the transmission. so, in mid to late 87 they added this in place of the plate you saw earlier. basically it’s only job is to cushion engagement from neutral or park, especially at high idle which most fuel injected cars seem to do for a short period of time after start up. these are prone to having the center pin of the accumulator. there is also a check ball location beneath it. do not put it in the wrong port as there is an orificed plug next to the check ball location.

now i said earlier that there was a valve that is pretty much a dead slug in there. GM actually has a valve set up for hydraulic engagement of the TCC in place of the TCC solenoid and computer controlled engagement. most transmissions never got it and the factory installed two aluminum plugs in the passage to render them useless. sometime in 1989 they quit casting the bore in the valve body, but up until then you could remove the two aluminum slugs and put in the hydraulic valve set up for hydraulic TCC engagement. Companies like Superior make a kit to retrofit this valve into your transmissions so you can do away with the electrical lock-up all together. i have never done one of these, so please don’t ask me what is involved. i do believe the part number though is a K017, and is currently around 100 bucks if you shop around.

For performance, it seems GM had many parts that were corvette specific. so upgrading several parts in your 700R4 with corvette calibrated components seems to be a going theme. the TV valve in this case may not allow an upshift to 4th gear past 3/4 to full throttle. here you can get a different “corvette” sleeve for the TV valve in the valve body to correct this.

well, this is the last i am writing on these trannys for a while- my brain is fried now i need a cup of coffee!

Parasitic Drag/Oil Shear Effect on Clutch Packs

so something i have been trying to find a happy medium on transmission builds is what is largely known as parasitic drag. this is the amount of power it takes to make the transmission function. on a stock th400 it is around 30-35hp it taxes off the engine, whereas a th350 is about 10hp less than a th400 on the average.

parasitic drag i always thought was due to rotating mass and power requirement of the hydraulic pump. simply put, a hydraulic pump needs power, and the resistance to flow creates a power loss as well. you also have slippage in the torque converter as it is a fluid coupling(essentially a pump). internal components also have some weight to it. basically the more it weigh’s- the more it takes to get it moving. i’ll spare you the law’s of physics.

there is also something i have been trying to deal with lately called oil shear. on your clutch packs, oil circulates from the center out for lubrication and cooling. when the clutch is not applied, the surface area of both the clutches and steels are still covered in circulating lubricant oil. now, if we are spinning a dissengaged clutch pack at any kind of an rpm, the oil will sling to the outside…..literally sucking the flat clutches and flat steels together and causing them to drag. i want to say it is fairly similar to a kind of capillary action caused by centrifugal force. obviously a dragging clutch pack will increase tranny temperatures, and if severe enough, clutch failure.

the solution is basically put a relief area in the clutch pack for the fluid to escape. the easiest way to battle this is to loosen up your clutch pack clearances. this though is a catch 22 as if your clearances are too loose you will have other consequences.

the use of radial grooved clutch discs and waffle clutch discs are the best solution to resolve the problems caused by oil shear on most of your older trannys. gm did it on different clutch packs in both the th400 and the th350.

later model 4L80E’s and 4L60E transmissions used what is termed as turbulator steels. basically they are steels that have an oblong hole in the middle to relieve the oil shear caused by centrifugal force. they are found in the 97 and newer 4L80E’s in the overdrive clutch packs.

on the 96 and newer 4L60E’s , they used turbulator steels in both the reverse input drum and the low 1/reverse drum. ironically it is erie similar to the same areas that fail on a th350 in a demolition derby….anyways the late model turbulator steels can be swapped into earlier 700R4’s as an upgrade.

now as an example of oil shear. on my 1st/reverse th400, i got a guy that gives it time to shift, but floors it from one side of the track to the other all night in forward. after 40 minutes of running the piss out of his suicide lincoln……he loses reverse or it starts to slip. upon teardown there is nothing wrong with the seals- the seal rings-the pistons- the forward clutch is fantastic- gearset is fine. the direct/forward clutch is burnt to a crisp- i mean no linings. on a 1st/rev the direct drum spins just as fast in the opposite direction but dissengaged. even when using stiffer trans brake springs to keep the clutches dissengaged- the discs still suck together!

this is chronic oil shear….and can happen on ANY transmission used for demo derby. even with the use of waffle clutches, chronic oil shear still can happen. we are experimenting even to this day with combinations of different linings-number of discs vs number of steels, different fluids/additives, and clutch pack clearances to prevent this. there is no answer at this time for derby transmissions.

4L60E Valve Body

the main difference between the 700R4 and the 4L60E is the valve body in my opinion. unlike the older transmissions….and very similar in the scheme of things to the 4l80e and other modern trannys, the valve body is constructed out of aluminum instead of iron and is computer controlled. the valving seems somewhat elaborate but to be honest, there are only a few areas you really need to concentrate on while servicing these valve bodies. the ATSG and the aftermarket performance  manual i bought on these trannys left a bit to be desired, and of all things i had to spend quite a while digging around to come up with a version of servicing these valve bodies that makes sense. one builder will tell you the whole damn thing has to come apart……..another builder says replace the force motor- clean it-say piss on it…….yet others replace the seal in the accumulator and buy a new mid plate! so, figuring that i write a lot of this for the do- it -your-selfer, i am going to attempt to guide you through one as simple as possible.

like i mentioned in my previous article about the front pump, the achilles heal of these trannys is the extreme wear of the valve body because it’s made of aluminum, although for the most part the valving is not steel. while some valves wear excessively- others do not.   have an ATSG manual handy for referrence. 

S3700072First thing to do is to remove the forward accumulator. there is a lot of tension behind this cover so when you remove the small screws take note. there will be two springs and a piston underneath the cover. the larger one is for the accumulator and there are different ones for different applications. the piston can be either plastic or aluminum. to the right of the piston under the cover is the low overrun valveand spring. remove and set it aside…..below that is yet another valve in the same passage…..this is you forward abuse valve. and this is one of the points you will have to check later. S3700056there is a doweled plug in this passage holding the abuse valve and spring in. i am pointing to the dowel in the photo. this same style retainer is used in a few other valves in the body as well. simply remove the dowel and the valve comes out. back to the picture above… the right of the accumulator cover are your two shift solenoids, A and B. the computer uses these solenoids to fire off the different gears. they can be checked using 12 volts and you will also need to make sure the ends of em are clean of debris. valve A has some spring tension whereas valve B does not. it is no where near as much tension as the accumulator. the valving below these 2 solenoids can be ramoved as well and set aside if you chose to, and is not a bad idea but can be time consuming and frustrating. coax em out with a small screwdriver but do not slam the valve body on the bench to get em out! you will fuck up your valve body and be in deep shit. remember it is aluminum……also remember it has sharp edges and will cut your hands nicely.

next to come out is our force motor. this is removed via a clamp and a bolt. there is no way to check this with 12 volts so you should shit can it and buy a new one during a rebuild. S3700067if for some stupid reason you need to re-use it, be sure to clean the screen at the end as it will fill with debris. below the force motor is the valving for it. it is removed by pulling a clip out the top of the valve body….similar to the two shift solenoids. the clips can fly off to neverland…….and the plug, spring, and valve can take flight as well so be aware. this valve is called the actuator feed limit valve.

the last thing that has to be removed is the 3-2 downshift solenoid. 1996 and newer used and on/off type solenoid that can be checked with 12 volts. older, earlier models used a pulse width modulated solenoid that is a throw away cause you can’t check it. sometimes the 3-2 solenoid has already been removed during main disassembly so you could get the TCC solenoid out of the pump. basically it’s a plug-spring-and valve below the solenoid if you chose to remove em.

with all electrical removed from the valve body, you need to clean the valve body with solvent and dry it. the two spots you have to concentrate on for excessive wear are the forward abuse valve and the actuator feed limit valve below that force motorS3700063(the one you throw away and replace). these two have to come out and get checked. with a clean valve body, shove the abuse valve in the body and shine a flashlight down from the top while looking down in the port. if you see a shit ton of light resembling the moon……it will leak and needs to be repaired. if you see very little light, then it will be fine. it is impossible to check this with oil on the parts as they will fill the gap….so it all has to be dry and clean to see the wear.


theS3700069 actuator feed limit valve needs to be checked in the same manor, except there is a problem the part you need to check is blocked by the outside of the valve. my index finger is pointing to the front of the valve and middle finger pointed to the wear point you need to check. to make this check, i basically found another valve and cut the end off it so i could see the light… to speak. the force motor replaces both the vacuum modulator and governor found on the older trannys and is the main component the comuter uses to control fluid pressure… motions several times per second like an electronic fuel injector and needs to be adressed above any other component in the valve body.

Sonnax makes oversized valves/tooling for both of these valves….as well as other valves throughout the valve body. the stuff is expensive. if you aren’t planning on doing a whole hell of a lot of these and need these fixed, try and find a local tranny shop to fix it for ya with their tooling or bite the bullet and buy a new valve body. now i have to admit , i only remove the solenoids and these two valves first. if both of these valves look good, i will stick a pocket screwdriver in the rest of the valves to make sure they move and the springs are working, check my solenoids, and put the damn thing back together with a new force motor/pulse width modulator. if they aren’t worn in these two areas…..more than likely the rest is alright.

the last thing to check isS3700062 the pressure switch assembly. this is the view from the top side and in the picture  S3700061to the left, i am pointing to the oil temperature sensor. the switch assembly here has  5 ports that need to be checked. 3 of them are normally open and two are normally closed. basically you take an ohm meter and check them for function by pressing the center of the switch with a small punch. these are simply on-off switches so if you have a continuity noise maker on your ohm meter that’s all you are looking for. there is also a resistance per temperature spec for the oil temperature sensor. this piece is basically what the computer uses to monitor what the hell the tranny is doing. basically if what this thing tells the computer to do:doesn’t match what the computer is tellling it what to do: it sets off that wonderful idiot light on the dash and creates drivreability issues. both of these tests are outlined in your ATSG manual.

700R4/4L60/4L60E Front Pump Service

 Fundamentally, all automatic transmissions use the front pump simply as a hydraulic pump. it’s like a farm tractor uses a pump to run implements by supplying oil to the control valves- then to components to create a function. on a tranny we use the outer shell of the torque converter to drive the pump- then send the oil to control valves that dictate what comp0nents need to be fired off to create function.

On these transmissions,as well as the 4L80E, this is where they really set themselves apart from the older generations of trannys like the th350 and th400.S3700012 the older trannys used a gear type pump sandwiched between two  iron halves. they are known for wearing the gears into the pump halves creating internal leakage and loss of pressure. the end play is also adjustable via the washer at the back side of the pump around the stator hub. here in the picture is a newer style hydraulic pump made of aluminum. the thrust washer on these is not the adjustment however- the adjustment for end play is on the front of the input drum. they also switched to a vane style hydraulic pump over a gear type pump.  it also contains two of the control valve assemblies: the pressure regulator assembly and the torque converter clutch valve assembly.

there are several vanedifferent pumps and combinations throughout the years, so here again unlike the older trannys, the pumps cannot necessarily  be swapped around and are year specific to an extent. early 700R4 pumps ad a different size stator and smaller input shaft….and are considered undesirable. in the mid 80’s they beefed up the input shaft. early 700R4’s up to around 1987 also used a 7 blade vane pump. they are known for failure and also had an outer slide that was a fail point. later models beefed this up to a 10 vane pump and a hardened outer slide ring. later years of the 4L60E used a 13 vane pump. now, this was primarily done to smooth out oil flow for a more consistent output: better driveability. they all put out the same amount of oil flow. a 7 blade pump is considered obsolete if you ask me and if it were me , i would replace it with a 10 vane pump and ring set up. a 13 vane set up is kind of like 10 lbs of shit in a 5 lb bag. under high hp applications it can crack. so to me, if you have a 7 blade pump, i would upgrade to a 10 blade. if i have a 13 vane pump: if it is in good shape i would re-use it. a 10 vane i would simply check it for wear. at the very least if you want to re-use a 7 vane pump buy a new outer slide ring. also when switching around pumps, remember there are different witdth’s of pumps and cover halves- so be year specific. the wrong pump in the wrong half and you will be in deep shit!

there are a few seals for the gears in these pumps and are supplied in an overhaul seal kit. vanes can be replaced individually for wear. the front pumps of these are also known for the front seal comming out. early model 700’s are known for this and GM came up with a retaining ring that fits over the seal. if you don’t have one of these  on the tranny you’re working on they can be had cheap(scrap yard core pile) and are not a bad idea.  i have heard of guys drilling the drainback hole out larger in the pump cover to prevent the seal blowing out…..not for me i guess. also it is worth noting that newer style 4L60E pumps have a different converter support bushing in the front and some builders feel they are better. if necessary to replace a bushing, if it needs to be staked in place do it. the bushing will walk out of the front of the pump and take out the seal.

aside from inspection of the pump, the other areas you need to deal with in the stator shaft pump_valves_lineupcover/rear cover are the two valve passages. both the pressure regulator valve and the TCC valves are steel….in aluminum bores…..yeah it is a high wear area and MUST be checked. pictured here is the regulator valve and TCC valve locations, along with a referrence to modifications described later in this article.

 if there is a lot of slop around either valve……when you get hot weather and that fluid gets hot…..all sorts of goofy shit will start to happen. on the regulator valve it will basically lose optimum system pressure and cause all sorts of long term damage from slipping bands and clutches…..especially after you get a trailer full of scrap behind the truck on a nice july day. same thing with the TCC valve- good hot oil and you have oil leakage- the Torque converter will lock and unlock- slip. it will feel like you are riding on a bull if it gets extreme enough.both of these problems as odd as it may seem- may go away in the fall and winter. thicker oil and it won’t leak- or a can of lucas oil.

to be honest, checking the wear on these valves is a pain in the ass. i remove them- clean the housing real good and stick the valves back in the bores dry. if they seem real sloppy they need repair. Sonnax makes repair kits for both of these valves. you basically ream out the passage and install an oversize valve. the tooling is expensive as hell, it is usually cheaper just to buy a brand new pump or at least a new stator half than it is to repair the passages. so make sure you don’t have to repair these valve passages BEFORE you order pump parts for the vane pump. it will be cheaper to buy the whole damn thing. also on the regulator valve, there is a land you must either grind off or buy aftermarket. it is a service bulletin from the mid 90’s from what i can gather and is in the ATSG manual. it’s pretty simple. it is to improve lubrication and reduce pump fluttery noise that can occur.also i found referrence to also modifying a land on the TCC valve and changing the spring….also listed in the picture above, but they ARE NOT described in the ATSG manual, so all i can say is if you chose to do what is in the picture it is at your own risk, consult your tech manual and/or valve body kit you may be using.

the pressure regulator also contains the reverse boost valve and the throttle valve boost valve, or TV boost valve.boost the TV boost valve was also a problem area of these older trannys, and there are several different sizes available. as a rule of thumb, i always install a .500″ diameter boost valve. in the picture it is the one on the left and is the first one to come out of the regulator passage after removing the retaining clip. the larger diameter boost valve allows the throttle valve to ramp up pressure quicker for a better clutch apply. some builders prefer a .471 diameter over the .500″ diameter for driveability reasons. i prefer the .500″ simply because i rather have a stout shift than a burned up tranny in 6 months.

now i know iS3700041 have missed a few things here, cause there is a check ball, orfices, and what not, but i hope it gave you some idea of the major things to address on one of these new style pumps. also don’t forget to replace this straining screen. it keeps the shit out of the the TCC circuit i think. if it plugs it will do all sorts of goofy shit too……but if it is plugged the it is probably from stuff elsewhere that failed anyways. don’t forget to replace it. you get one of these in the overhaul kit too.

Torque Converter Clutch Hot Wiring

Well  to answer a few questions i have gottenon a 700R4( and 2004R) , they obviously have what is called an internal torque converter clutch, or TCC for short). as i have gone over before, it is basically a wet clutch applied by the transmission to lock up a torque converter for mileage. it is usually engaged by the computer control from the factory. now, there 700R4’s that had lock up internally in the transmission without any external computer control. gm actually originally designed the valve body for this, then quickly converted it to computer control primarily for emissions/mileage reasons. most 700r4’s have aluminum plugs in the valve body where the original tcc valve would have gone. you can retro-fit the valve body with aftermarket parts to do this as well. i have never done one or ran across one yet, but i know it can be done.

BUT,  we are all cheap bastards, so usually what is going on now-a-days is swapping these older overdrive trannys into street rods and plow trucks for mileage…..or we simply had a working tranny laying around from an old derby car we gutted and th350/400’s are getting hard to find.

So, when doing a swap into another vehicle, the only real critical thing you need to worry about is adjusting and installing the throttle valve cable correctly. the electrical connector for the TCC can be left unhooked.  OR if having one rebuilt, you can simply install a cheap kit into the pump and omit the clutch all together…..which is what i did. however this causes you to lose some efficiency and mileage due to the converter slippage.

to be honest even though it has a 4 prong connector hanging out of the case, the actual engagement of the TCC solenoid is a 2 wire solenoid with one grounded and one 12v power source. GM used several different wiring formats throughout the years some using as many as 4 pressure switches …….some only one. this is because gm was trying to lock up the converter in more than one gear…..which probably led to pre-mature tranny failure.

the way i wire it up it to basically drop the pan, rip the 4 pin connector out of the case and install as single wire kickdown plug from a th400, then run a single power wire from the 1 pin th400 connector to one side of the TCC solenoid. now, the other wire off the solenoid is ground. i then use a pressure switch in the 4th gear passage  on the valve body as a ground. there is usually one there anyway, but you should make sure you got the right one.

this way no matter what you do for power, the TCC will only engage in overdrive. you can run the ground wire off the TCC solenoid straight to ground but if you forget to shut off the switch, it will stall out the engine and scare the shit outta ya. i would either use the ground switch or leave the tcc unhooked all together.

now, if you have any idea what i am talking about by now, you can figure out that you could just wire the damn TCC to a toggle switch  on the dash and lock it up whenever you want. by using a psi switch in the 4th gear port, you basically can flip the switch for highway driving and as soon as it hits 4th gear you got lock-up. for in-town/city driving you can leave the switch off pretty much cause a TCC doesn’t doo much good on these trannys in heavy traffic anyways other than tear up the tranny faster.

the pressure psi switchswitch you want to wire to is the one marked letter “A”. this is the 4th gear pressure port. GM used both normally open and normally closed switches….both single and 2 pronged. i like to use a single prong normally open/psi closed switch. i believe the GM part number is GM#8627332 . now some valve bodies didn’t use and psi switches at all and simply have 1/8″ pipe plugs. if you decide to do this, you can omit the rest of the psi switches and replace em with pipe plugs to save confusion later on. you can also modify your wiring and make whatever switch you have on your valve body work to engage the TCC only in 4th gear.


here is a rather wiring tcc terrible drawing of how the wiring goes. the red obviously is 12v and the blue is ground to the 4th gear psi switch.






now, if you do not like the idea of just using a toggle switch , or the driveability using a toggle switch isn’t to your liking,  you can then take the 12 wire and instead of wiring it to a toggle switch you run it to a low manifold vacuum switch….then a brake pedal switch… series….before you get to the transmission. the part numbers on these components i believe are a Low-vacuum switch – GM #14014519 and Normally open brake cancel switch – GM #25524845 .

 the low-vac switch so the converter will unlock in low vacuum situations, such as going up hill and heavy throttle.  The brake cancel switch unlocks the TCC when the brakes are applied.  Trucks that came stock with 700R4 trannys came with a low-vacuum switch and a brake cancel switch.  The stock low-vac switch didn’t let the TCC unlock soon enough with this mod. the vacuum on the stock switch kicked in at 3.5″, meaning the vacuum has to get real low before it will unlock.  The vacuum switch part number above  kicks in at 7.5″, which will let it unlock sooner giving you a bit better performance. The brake cancel switch on 700R4 equipped trucks also disconnects the cruise control (if equipped) when the brakes are applied

Now to the outside wiring. run the power wire from 12v key on hot through a normally open brake cancel switch.  This switch will allow current flow, only when it is depressed.  The brake pedal depresses the switch, normally, and releases the switch when the brake is applied.  This switch works exactly opposite the brake light switch, whereas the brake light switch allows current, only when the brake pedal is depressed, the cancel switch interrupts current when the brake pedal is depressed, thereby unlocking the torque converter clutch, such as in a panic stop.  The cancel switch is mounted on a bracket under the dash.  The brake pedal arm makes contact with the switch when it is all the way out.  Just so you will know, most of the time the brake cancel switch is also a cancel switch for the cruise control, if you have cruise.  This is why it is called a cancel switch, it cancels power when the pedal is pressed.  You need to make sure that when the brake pedal is all the way out there is power going through, press the pedal and the power is interrupted.

From the brake cancel switch, power is routed through the low-vacuum switch.  use a junkyard donor for the plug if you can as the prongs are close together and can be a pain in the ass. you can probably find most of these parts in a junkyard if you look in the right spot.  If you can’t find a plug, you can either use some slim female spade connectors or solder the wires on.  Mount the low-vac switch on the firewall or at the very least away fro mthe engine a bit.  Then connect to the new single-pin connector at the transmission .


you have pretty much just made yourself 120$ lock up wiring kit for a fraction of the cost. enjoy!

TV cable adjustment 700R4 overview

Now, a 700R4 even when i was starting out seemed intimidating and we would all chose a 400 or 350 over one cause you simply did not want to deal with the added cost of the build and the damn throttle cable. with the high price of fuel and the availability of these trannys these days, they are now the go-to choice for street applications when you are going to retro fit an different driveline into an old car or custom street rod. to be honest, it is a lot easier than you think these days.

The overall goal no matter what when adjusting the cable is to simply adjust the cable to fully seat the throttle valve fully shut at wide open throttle. stock cables are adjusted by depressing the button at the end of the cable that mounts behind the carburetor/throttle body. you  back seat the stock cable  to the rear of the car to take up slack: to the front to create slack….much in the same way you would adjust a parking brake cable. if you are using  a universal cable , you pull the cable tight and clamp the cable in place @ WOT. whatever it takes, you want full open at wide open throttle with the right geometry to the throttle shaft centerline.

if you are retro-fitting a 700R4 to an older chassis, it is a lot easier to use the proper brackets either stock or aftermarket for both the carb throttle linkage and the cable end hardware. when using the right brackets, adjustment is as simple as openning the throttle to wide open throttle and adjusting the cable to seat the valve(pull it all the way out). holley and edelbrock both make brackets for the 700R4 throttle cable. it isn’t worth dicking around with making your own linkage unless there is no alternative, and there usually is.

if you want to be adventurous(cheap shit) and want to modify the carburetor linkage without using an aftermarket kit, it can be done. from what i can gather, you are basically going to  measure 1 3/32″ off the centerline of the throttle shaft to get the right action on the throttle cable you have to get 30 to 35% of travel must be behind the vertical centerline of the throttle shaft. this is about 1/2″ to the rear of the throttle centerline at idle/low speed usually.

the other 65-70% must be to the front of the centerline of the throttle shaft, or about 1″ from the centerline of the throttle at wide open throttle….or WOT. this is to ramp up oil pressure faster off idle. if  you don’t get the throttle action lop-sided, there will be a constant pressure rise which results in trans clutches burning out…….and you wreck your tranny basically.

DO NOT ADJUST THE CABLE TO MAKE IT SHIFT HARDER. DAMAGE WILL RESULT. use a shift kit or modify the governor to change your tranny shift characteristics. so if anyone has told you to either do that or leave it unhooked…..they are full of shit.

700R4/4L60/4L60E Input and Forward Drum Service


well since the input and reverse drums of this family of transmissions overlap and are very similar for nearly 20 years, i didn’t see the point in dividing up the articles. as you have probably seen this picture before, but this is the input/reverse drum assembly out of a 4L60e, but is identical for the most part to any of the other trannys. this is pretty much how it comes out of the tranny. you can also see the 2-4 band in the picture.



rev drum

the job of the reverse drum in this transmission is primarily to be a holding member for 2nd and fourth gear to create planetary action. the 2/4 band basically locks against the outside of the drum in an identical fashion to a low 1/reverse band in a th400. the sheet metal teeth on the outside of the drum engage your sungear shell. to the inside of the drum is your reverse clutch pack. it is typically a 4 disc clutch and can be serviced pretty much like any other clutch pack out of a th350 or th400.  basically the 2/4 band is dissengaged , the clutch packs of the input drum are dissengaged, and the front of the input input drum drives the reverse drum to give reverse.

the outside of the drum is known for excessive wear and if damaged should be replaced during a rebuild. it will wear just like steels in a clutch pack….primarily during the 2nd gear shift. if it is minor wear you should take some emery cloth and at least scuff the surfaced up so the new 2/4 band gets worn in correctly for proper shifting. overall pretty simple but not to be overlooked.

theinput input drum assembly is next. outside of the low 1 holding clutch to the rear(same as a th350), and the reverse drum clutch, this houses everything else pretty much. in a nutshell it seems complicated as hell, but it really isn’t that bad. most of the pistons sit to the rear and all the clutches sit to the front….and there is really only one spring you need to compress to get everything out. pictured here is what the drum looks like as it comes out. you can see the cast sprag to the front that engages the reverse clutch pack. check this quick for gouging and wear. at the base of the input shaft is your sealing rings. now they used several sealing rings over the years. it is pretty much an industry standard that whatever it did have: put the one piece teflon sealing rings back on it during rebuild. and yes it does require some special tooling.

youS3700040 pretty much flip the thing over and drop out the clutch packs. first thing is you remove the outer snap ring, 3/4  pressure plate, clutch pack,  and apply plate(yes there is a pressure plate on both ends). this is your 3/4 clutch pack assembly and can have up to 6 discs/steels. you may also have return springs that fit in 4 spots to the outside of the clutch pack between the drum and pack. these are return springs. some builders leave these out to make the shift quicker and better clutch apply…..sometimes they were never in there to begin with. if they are there, i recommend putting em back in unless there has been a shift kit installed of some kind. the outer pressure plate thickness can also vary so if it is damaged, make sure you get the right thickness to insure proper clutch pack clearance. these are known as a problem area and they make specialty cluch set ups for these like the Raybestos Z-pack to remedy failure in extreme applications. depends on what your application is for during rebuild.

once that is out of the way, S3700039the next one down is the forward clutch. pictured here is a second snap ring….which sits below the 3/4 apply plate. once this is removed pretty much everything else will fall out as far as clutch packs so don’t panic. this is where if you have never done it, you remove the ring….slam it on the bench….and panic when all sorts a shit come out. this is what a diagram in an atsg manual is VERY helpful. 

anyways out comes the snap ring, forward clutch pressure plate(which is also variable thickness) and  forward clutch pack with bottom wavy steel come out with the forward sprag assembly usually. there is at least 4 clutches and steels the sprag assembly should be set aside for later inspection.  below the forward clutch is your overrun clutch set up. the backing plate for the overrun clutch is also your apply plate for the forward clutch… if you can take note on how it came out so you don’t get frustrated during re-assembly. the overrun clutch is only 2 small discs and two steels.

at this point, you are down to removing your pistonsS3700037. this is the only real spring pack you need to remove. as you can see here, i made up a small tool with a few bolts and a piece of flat steel, then chucked it into my lathe and used the drill chuck as a compressor. there is a tool for doing this….i’m just a cheap shit and this cost me 20 minutes of time.  now, when compressing the spring pack here only compress it like an 1/8″ or less! there isn’t a lot of free travel under the spring clip here so just push it enough to relieve tension on the clip…then wrestle the clip off. i believe the reason for the lack of compression space was to keep the material as thick as possible in that area of the drum. the area of the drum below the retaining clip is a fail point and there is even aftermarket sleeves offered by sonnax to beef up this area for heavy applications and big power.

once the clip is out, you pretty much can pull out your pistons. S3700036the first set out is the overrun clutch piston(center), the forward piston(middle: holds the overrun piston), and forward piston housing. this picture by the way if how i put em back into the drum as an assembly….they may come out individually.  below the forward piston housing is another return  spring, the tin apply ring(looks like a cheap piece a shit with long fingers) and the 3/4 apply piston. now….you’re empty and you can clean, inspect, and rebuild. now, depending on the year and model, your input drum may have aluminum pistons with seals, molded seals that are made into the piston(require piston replacement), or a mix and match of both styles of pistons. most people prefer the molded pistons for the 3/4 apply piston, however  i think it really depends on the year and the application…..and your budget.

here is a photoS3700031 of the 3/4 piston to the right- apply ring, and forward piston housing.






here S3700029is a picture of how the piston assembly is layed out from right to left, right being the bottom and left being the top. you can buy all this as an assembly from your parts suppliers if you have chronic damage of want to use modern pistons in an older 700R4






hereS3700025 is the forward clutch sprag assembly.  this can be a fail point and should at the very least be popped apart to check for cracks and what condition it is in. a double cage 29 element sprag is preferred for these and some of the early trannys had a weaker sprag. enough years have gone by though that if it has been rebuilt, someone probably already revamped it. it basically is a one-way lug type sprag that locks in gears 1-3 and overruns in overdrive….basically driving the entire transmission. so if there is a problem, you don’t check it….you’ll be in deep shit. the two disc overrun clutch meshes with the smaller side of this assembly and when locks gives you engine bracking, otherwise the clutch will overrun allowing you to coast. 

re-assemblyS3700027 is not that bad after you do it once. first, install the 3/4 piston. i use a feeler gauge but some kits come with an installation tool….and there are specialty install tools as well. once in, put on your apply ring and spring, then what i do is assemble the rest of the pistons as pictured earlier and install them as an assembly. then re-install your springs. the first clutch pack in is your overrun clutch pictured here. i am pointing to the seal here that MUST be replaced. this seals the center of the input drum to the output shaft. don’t forget to put it in. i usually put it in first before any clutches. it’s splined on the outside and is hard to miss in the rebuild kit. also when putting the apply plate for the forward clutch on this, make sure you put it in right. the rest of the input drum is pretty much stack and go. like any other tranny, you should soak your clutches. on these trannys i prefer to always replace your steels with your clutches it’s money well spent!

GM 4L60E Teardown Pt. 2

now for the second part of this tear down, we are basically going to break the transmission down into it’s major components the rest of the way. in a nutshell you then rebuild and go through each component separately then re-assemble.

S3700002after the valve body has been separated as described in part one, next i go to the 2-4 servo cover. this applies the band on the reverse drum to give you a holding member for 2nd gear and 4th gear. it is held in by a spring clip and is stubborn as hell. the atsg manual gives you this as a starting point….and the youtube video’s give you the impression that it falls out. well, it is corroded and is a bitch to get out. soak it in wd-40 and tap it into the tranny to get the pressure off the clip. you then either pop out the clip…..or like i had to do….chisel the rotten rusted thing out of the case and try not to bust the case. once the clip is out you are suppose to use a pair of pliers and simply pull the cover out….snip off an remove the o-ring on the outer cover-and the whole works falls out. in reality if it is siezed in the housing like mine was, you put air pressure on the back side of it via the ports under the valve body while coaxing it with a rubber mallet. this is why i prefer removing this after you pull off the valve body, just in case you have a nasty core to deal with.


next, ifS3700004 you have not already done so, remove the tail housing. i recommend that you pull the tail housing WITH the speedometer still installed if you can. they are prone to breaking if you try to pull em out from the outside. after removal you can use light pressure from the inside and pop the speedometer out of the tail housing from the inside. you can also see what i call an oil shield in this picture. unlike a th350, the tailshaft comes out to the rear of the case so this does not need to be removed.


Now, for pump removal. there is no tapped holes on the front pump for a slide hammer toS3700012 be installed as you would do in an older gm or chrysler transmission. so basically after you remove your pump bolts you can use a specialty tool to pull the front pump out using the stator shaft……or like many gm transmissions you stick a large screwdriver behind the pump through and openning of the valve body side and pop the front pump out by prying against the reverse drum. here again there is no picture of me doing it cause there is youtube video’s and atsg manuals to go by in this instance: a demonstration is a bit more appropriate if you have never done it.



after you have the pump removed, your clutch packs can now come out. the front 2-4 band can be removed first. it may not seem like it but the band can be coaxed out first with a large screwdriver. if the locating pin has not yet come out of been removed already, it can be popped out from the backside of the pin to help in band removal. after the band is out, the reverse and input drum assemblies can be removed in one glob. also in the picture you can see the the front planetary sun gear as well. this can also be removed at this time and set aside. the input and reverse drums can be separated after removal as they are serviced separately:it is pictured assembled as this is how it looks comming out.


next it is time to remove the retaining clip holding in the rest of the front planetary, the output shaft, and sun gear shell assembly.S3700010 i have it removed from the case. it is a pain to get to, but it is basically removed similar to how a th350 tranny comes apart. the exception being that the output shaft will usually fall out once the clip is removed: so make sure you are prepared for that. do not worry about damaging the clip removing it as you should replace this clip….and it usually comes in a good rebuild kit here you see the fron planetary set with clip laying on top and output shaft. the sun gear is removed as well and simply pulls out of the case


now, to S3700014be honest the rest of this tranny is damn near identical to a th350. here now you are down to the center support containing your rear sprag, rear planetary gearset, and you low 1/reverse clutch pack. this is basically a th350 set of but it has tighter tolerances than the th350. so it makes removal and installation a bit more of a pain in the ass. nothing to be alarmed about though.


at this point your 4L60E should be apart on the bench. each component should be checked over, rebuilt, and appropriate parts replaced at this point.  the case, the gearset and center support, front pump, input drum clutch assy, reverse drum/band/servo assy, and the valve body should be looked at as if they are separate units. approaching a build like this will make comprehending and servicing your transmission a lot easier. it can be overwhelming( if not intimidating) if you try to look at it as if you are doing everything at once.

re-assy is fairly easy once everything has been serviced. if you have done automatic trannys before, it is rather simply. if not, use an ATSG manual and you will be fine as long as you have a bit of patience.

GM 4L60E Transmission Teardown pt. 1

i am going to begin disassembly of my 4L60E.  many of the same internal parts of this line of transmission apply to the 700R4 with the exception of the valve body components. so i am going to deal with the removal and inspection of these separate. first off the biggest difference is that we have an aluminum valve body instead of cast iron like the older trannys. so use caution when handling it as the edges are like a knife if you get careless!


S3700015So the ATSG book said to start with the 2-4 servo cover here-the book i got from summit racing said to start with the tail housing. personally to save you a headache start with the valve body. after busting some components trying to follow the atsg manual, i would say start by removing the oil pan, filter, and wiring harness.i didn’t get a picture of it complete with the wiring harness but here it is after the harness is removed to give you an idea.




when removing the wiring harness, the solenoid right above the torque converter clutch solenoid must be removed. i believe this is the 3-2 solenoid to the front of the valve body. it is simply held in by a spring  clip just above the solenoid….and will fly off across the shop. these solenoids were pulse motors early on and later were a more simple on/off style solenoid.



 hereS3700006 we have removed the torque converter clutch solenoid, or rather TCC. this MUST be removed prior to pulling the pump out otherwise you will break the damn thing off. as you can see that’s what i did cause i was following the wrong manual. it is wired in one piece to the harness and comes off with it rather than just a connector like everything else. these are prone to cracking causing converter failure. you can check these with air pressure if you are careful, but if you have an older one and are unsure- spend some money.


hereS3700009 i have removed the pulse width modulator (PWM)solenoid so you can get a good viel of the connector going through the case. there is a special tool to remove the connector via pressing the fingers on the top of the case and pushing it through the bottom. you can also use a buddy with small screwdrivers while wiggling it- or a large socket. the prongs will break if you just yank it out. you can leave the pwm in and remove the valve body first to remove this connector a lot easier.


NowS3700045 at this point you can turn either turn you attention to everything else and remove the valve body last, or remove the valve body and stuff now and set it aside for later service and inspection. i am going to go the route of getting the valve body the rest of the way off. next out after the harness remove the pressure switch manifold and set it aside. you can also see it’s location in the first picture above. i would also remove the selector tension spring at this point as well just to make life easier later on.


nextS3700073 remove you valve body bolts and your valve body assembly. there are check balls located on both sides of the transmission  separator plate and can vary with the years, so have the tranny inverted and pull the valve body straight off. usually the check balls will remain in place…if not be stuck in the mid plate.  remove your check balls. the 1-2 accumulator is in the upper left hand corner holding everything in still as well as the plate to the rear.



hereS3700071 is when you can take note of your valve body gaskets and what mid plate you have. the mid plate is stamped with a letter designation and the orientation of the gaskets is also marked. if you are investigating a failure this is a place to stop and take notes to see if someone else didn’t screw it up at some point during a prior build….or you need a different mid plate. my fingers are pointed to a “V” and a “C” as the gaskets are marked.



 you can then removeS3700049 the 1-2 accumulator, rear coverS3700052 plate, and mid plate/gaskets. the bottom half of the 1-2 accumulator is below the mid plate and can also be removed. the pin  at the center of the piston pulls from the case. these accumulator pistons can be a high wear item so inspect them closely before re-installation. note the locations of the rest of your check balls at this time as well. here i am pointing to an encapsulated check ball to the rear of the case. this is suppose to stay in place but can fall out due to wear. this needs to also be checked out before re-assembly. also note the check ball near my thumb in the case that is loose. this one is easy to overlook during re-assembly so take note not to forget.


last thing inS3700051 this part of the tranny is the 2-4 band anchor pin. now depending on where you started this may just fall out of it may have to be pushed out after you remove the front pump and/or the 2-4 servo.  at this point you can also remove your selector shaft and parking lever engagements. you can now turn your attention to the rest of the tranny for disassembly.                                                             



GM 4L60E Transmission

well in this second section i will be going through some of the background of the 4L60E transmissions. somewhere between 1992 and 1993 the 700R4 became a computer controlled tranny and was/is redesignated the 4L60E/4L65E. It did not have a governor or throttle valve cable(TV cable) as the earlier models did. the 4L60E uses electrically fired solenoids for shift and what is call a pulse width modulator(PWM valve) in place of  where a governor and modulator valve would be on an older tranny. this is also referred to as a force motor by some people. The on- board computer then dictates shift points,  TCC operation, and overall function of the valve body. most of the mainline internal components are similar(if not interchangeable) with the 700R4. the main difference between the two is the valve body on the 4L65E is made of aluminum instead of cast iron and is fully computer controlled.

The 4L60E also received upgrades throughout the years as well. the 93-94 models had their own valve body set up/1995 was unique unto itself/and the 96 and later models also were different yet. in 1998 them made the housing a 2 piece design with a removable bell housing.

one thing with this line of transmissions over a th350 or good old th400, there were A LOT of different kits and what not. just looking through my book there are 3 different rebuild  kits for the older 700R4 and 3 or 4 different kits for the 4L60E, so getting the right kit for the right tranny and application is somewhat critical. you must also correct things on these trannys that aren’t even defective because they are common fail points. as a rule a thum- the older the tranny the more updates you are going to need. 

S3700001So, i got  this bastard 95 vintage core in on trade. unless i plan on sticking it into another 95 conversion van from connecticut that died out here… was a heavy metal band on tour by the way……….it was more cost effective to play with the older 700R4 and put this in the core archive for future use.  These things are all over the place….and i get probably 4 calls a month during the winter of these trannys going out in GM trucks moving snow.  i bet you pass at least 5 of em going to work everyday on the highway in operation. there are shift kits available and like the 4L80, there is performance software out on the market to adjust your shift firmness and timing via the laptop computer or aftermarket programmable module that plugs into your OBD diagnostic connector. i haven’t dealt with these systems first hand yet.