Transmissions Breaking, HELP!!!

[Livelli]

Ive got an '85 blazer w/ a 6.2 and a 700r4. I recently replaced it and the tranny mount with a "bulletproof" trans and shortly thereafter, the (grade 8) bolt going throuth the t-case support rod/bellhousing into the motor started breaking. I managed to get it out and replaced it. It broke again and whilie I was nursing it home from work (>5 miles) the new one broke too, then the upper pass side trans-motor bolt. Just as I was pulling into my parking lot I heard the rattle. When I crawled under the truck I found that the only remaining pass side bolt had held out, but took off a chunk of the bellhousing about five inches by three inches. I warranted out the transmission for a new one thinking the case was weak. I installed the new one and after a few days, the same bottom pass side bolt popped. Again I replaced it, again it popped, and again the bellhousing broke. I tried to warranty out this one and the company I bought it from voided my warranty. If anyone has had a similar problem and found a solution, I would greatly appreciate any advice.

 

[NateInChandler]

Are the dowl pins still in the back of the engine block.. If there is one missing or not tight in the back of the engine, it will not help to center the trans on the engine and you will start busting things up, we just had a 75 chevy 4x4 come in with this problem, busted the bellhousing all the way around, the only thing holding thefront of the tranny up was the force of the tranny/engine against eachother, the torque convertor and the strut bars.. Nate

 

[randy88k5]

The bellhousings on the 700 seem to be pretty weak. GM tried (and successfully it seems) to fix the problem. They put metal struts from the motor mounts to the tourque converter dust shield (the heavy aluminum kind), and one large strut from the 208/241 tcase to the bellhousing.

If you didnt have those to begin with, or you did not re-install them, that could be the problem.

Though it does sound like your problem is accelerated, check all the bellhousing bolt lengths and torque, check engine and tranny mounts and crossmember, check driveshaft length and slip ability, and make sure the bellhousing dowel pins are present and undamaged like Nate said.

 

[berserker]

time for a sm465.

 

[blackblazer717]

i think its time to ditch it for a SM and a 205....... hint hint*******
LUKE

 

[Livelli]

thanks for the input guys, I think the problem is one of my motor mounts. I'll be replacing both of them soon (before the new, new transmission). Shortly after installing the 1st new tranny, my drivers side x-member bolts slipped out (?) and the whole drivetrain droopped about +/- 15 degrees, probably straining the mounts exessively. And as for the Muncie 465 idea, Ive thought about it and beleive me, its tempting. But if I put a 465 into my blazer, It'll be a Cummins in front of it.

 

[83ZZ502_Jimmy]

Make sure you use the same type of mounts for the engine and tranny. i.e.- rubber and rubber or poly and poly. DO NOT mix them. It can cause what is happening to you.

John