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.

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