Last weekend I decided to install a torque convertor(2000-2200 Summit), front and rear oil seals, and B&M shift kit in my TH350 transmission. I removed the transmission from the car to do this. Finished up Tuesday night and other than pouring endless amounts of ATF (ran out after 9 qts, that converter really takes alot) everything went fine. Next day, driving to work was fine, but on the way home, it wouldn't shift out of 1st part of the way home, despite adding more fluid nothing improved. Then I noticed that it was leaking profusely from the pan and the front (either seal or the pump itself) I had it towed back. The failure happened after a hard under-load downshift, the first since the mods.

Here's the rest of the story: While reinstalling the valvebody, the S-link to the shifter linkage fell, naturally there was a hole straight below it, into the mysterious, frightening interior of the transmission. Endless strings of the familiar 4-letter-words (and a few new ones I invented for the occassion) didn't bring it back out, nor did flipping the trans on the engine stand and shaking it. ...or so I thought... I give up now and move it to the workbench, remove the pump (no slidehammer required) and start removing parts. I couldn't find it, but of course, it turned up on the floor where it had been on the stand Everything goes back in, using an old transmission rebuild book as a guide. I didn't replace any internal seals, nor the pump gasket although I used some gasket-making goo on that.

At this point I just plan to completely strip the thing and buy the $90 complete rebuild kit. I don't want to risk more downtime (this is my daily driver, currently bumming a ride) It does have 82k miles on it and that was probably the first time the pump had been off since the factory, it probably needed it anyway.

Sorry for the novel, please give me some ideas of what may have gone wrong in my reassembly. Could the pump be oriented wrong, or just leaking? Some else internal screw up?

Thanks for the help,
Chris

 

okay, so it's mostly apart now, the clutches look fine but the "band" is falling apart. If I can pick it up seperately I think I'll just do the seal-kit. The gasket on the pump looked to be in pretty bad shape.

Anyone else had this experience or have any ideas as to the cause?

Any other modifications while I'm in here (cheap)

-Chris

 

It's been a long, long time since I did a TH350, but it seems to me that a 350 runs through all of it's upshifts using clutch plates, not the band. I think the band was utilized in a manual downshift or possibly reverse. I really cannot remember. If your pump to body gasket tore on removal of the front pump, crossover channel leakage that can have an impact.

Hopefully someone more up on these units will chime in. Good luck.

steve

 

The most common reason a TH350 won't shift out of first is the vacuum modulator being bad or disconnected. The modulator is the can with the vacuum hose to the intake.

 

had that happen....If you put it in low and shift manually it should shift into 2 and 3 and you can normally limp home when this happens...

 

I've had the vac. module come off before too (after installing a new intake) It felt like that at first, but with the massive leakage I knew something else was wrong. "cross channel leakage" at the pump is what I think. I bought the rebuild kit, although I probably won't replace the clutches that I need special tools to get at. At least I can replace everything else.

-Chris

 

Talk about overhyped, that was easy! No special tools needed, just 2 C-clamps and taking due care. Replaced all the seals and clutch discs. It's pretty close to back together now, then into the car. Hopefully it'll be back on the road soon.

Found a strange foreign object in there that may have been part of the havoc... see: http://forums.corvetteforum.com/showthread.php?t=883671

-Chris