360 Modular Brace for TH400/Mid-Plate Pan Bracing

Years ago i came uS3700012p with the idea of putting in a mid plate between the oil pan and the transmission case. On a th400 aluminum transmission case, they can be prone to breaking at either the rear tail shaft housing or just up from it off of the locating lugs for the rear band. When the shifter is mounted off the back of the case, it becomes a weapon next to you if the rear of the case lets loose. i had 2 or 3 friends take one hell of a shot to the legs when it happened. So, by adding a plate off the 13 oil pan bolts to the rear 2 tailhousing bolts/ transmission mount, it prevents the shifter from comming over and nailing you.

of course, this has evolved into a complete underbracing solid steel oil pan. you then add a rear tailhousing plate and build gussets from the steel oil pan to the rear tail plate. in this picture to the right is a finished mauler brace pan. i named it mauler cause it reminded me of wolverine’s claws that shoot out of his hands. on this one,  i did not use a rear plate. i elected to drill and tap the tailhousing  so i could bolt the pan brace from beneath. this allowed a 4X4 crossmember to butt up to it and use a port-o-power to wedge it into the car.

there are some plus’s and minus’s to this. you have to use allen head screws to make everything clear. it ends up about a 4 quart capacity but has a smaller depth profile than the deep sump th400 truck oil pans.  it is damn near bulolet proof, but when you finish welding it up, it can be a complete pain in the ass to get it to seal at the pan gasket. also it can be a pain to remove for simple service. i highly recommend running good old dexron II/III and servicing your trans frequently. i would pull the drain plug after every run and change out the filter every 3-4 events…….or once a year. by circulating in 3-4 fresh quarts every run it keeps your fluid juiced up…..so to speak.

what a lot of people forget though is that those big nerat bell housings have a tendency to want to pull upward and off the front of the aluminum case as the car noses up. even with top bracing….it can still pull the bolts. simply drilling and installing two bolts to the bottom of the bell is all you need(also pictured). all it is doing it keeping the bottom of the housing from moving forward. think of it as a safety strap.

now with the big push of people either going back to more stock builds or selling out completely, i decided that htere has to be a more simple and easy way of doing this other than the freaky warlord monsters i have built. so i came up with a spider bracing plate. it fits over the stock oil pan with an access hole to pull the drain plug, so there is minimal sealing issues of fit problems from welding. it can be removed without dropping the pan and is able to be removed without battling your rear bracing plate/top bracing. it is bolted to the housing and the rear bracing plate.

you then run 4 tubes cross the top for your top bracing. you can build one of these elaborate spider’s web looking things for a top brace(i have), but i have had successful builds out there wil as little as four 1/2″ I.D steel pipes from rear plate to back of the steel housing. the distributor protector and/or the nerat housing takes most of the abuse of keeping the nose down on the car. your bracing is there to keep the aluminum case in tact. the nice thing is that this set up is easy and straight forward, cost effective, AND can be removed in pieces to comply with different rules. i mean you can remove all of it and swap on a J.W. Performance bell housing for a stockish approach……or drop the bottom spider brace plate if no skid plate is allowed at the track from under the car……or you are 4-6 hrs from home and something grenades in the transmission and you need to swap in a different center unit into all you bracing.

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