ok, I've been talking to some transmission specialists about the t-5. They all say that the huge weakness of the transmission is the case. When you feed it a decent amount of power, the case flexes, distorting gear alignment and tearing up the bearings. A couple have also said that they have seen the gm t-5 case being braced, and supporting in excess of 500rwtq without issue.

My question is this: Does anyone know where the case flex is induced? Where would it be most benificial to weld in the bracing? Or should I go hog wild and install bracing wherever I possibly can?

I also saw that www.5speeds.com sells a solid steel rear bearing retainer that is supposed to prevent the rear case area from distorting, and also gives a solid support area for the output shaft to sit on. Anyone know how well this works? They say on the site that the jags they sponsor were trashing 5th gear every 30 race hours, and since they designed and installed this they haven't trashed any of them. Being the sceptical person I am, my first thought was that they have only been in use for 25 hours. Any thoughts on that?

I have an opportunity to get a good wc t-5 out of a 92 rs, that was rebuilt maybe 10,000 miles ago with everything I need to install it including flywheel and centerforce clutch for $200. It's a family deal

My 700r4 is starting to slip, and I'd rather take it out of service before it goes so it doesn't ruin the new torque converter and trans cooler.

What do you guys think?

 

The weak point is across the front of the case; the thin aluminum there stretches, allowing the clutch gear and countergear to spread apart and misalign. Gear teeth is what tears up, not bearings; although, the bearings are too small, and if you have enough torque to overload the case, then it's enough to overload the bearings too.

I have a pile of cases I've accumulated over the years, that are stretched so bad across the front, that they won't hold fluid; it all leaks out around the front countergear bearing. Some of them it's so bad that the trans will run dry while parked.

All that the Gearzone bearing plate prevents, is the same effect on 5th gear. 5th gear ONLY. It doesn't strengthen the trans as a whole. Remember, 5th is stuck out in space, on the end of the countergear, with only the extension housing holding up the back end; in other words, it's just kind of waving around back there. The bigger bearing retainer stabilizes it.

I've never seen a brace for a GM case (or any other kind, since they're all about the same) that braced the place that would really make a difference. Seems like it wouldn't be too hard though; if you machined off the front of the case and bolted a steel plate of the same thickness to it, you'd think it would be quite a bit stronger.

No comment on the other trans. The word "rebuilt" seems to get toosed around quite a bit in relation to such things, but it often doesn't seem to involve anything internal.

 

It seems that if you're willing to brace a T5 all over the place you must be planning some pretty serious hp. If so, take the above advice and go with a stronger tranny. If not, if you're planning on up to 450 hp, the T5 can be built for well under $1K to handle it. Stock, it's rated at 330 ft. lbs., I think, and some pretty knowledgeable people on this site say they have run them successfully behind much more power than that. Also, the above adviser has some interesting advice on how to drive a T5.
If it's a family deal, do you have access to a T5 parts car?

 

That is exactly the info I needed RB, thanks

The rebuild included new bearings, synchro's, new 5th gear, reverse gear, reverse idler, and I -believe- a new clustershaft, but I'd have to doublecheck that one. The name of the clutch escapes me at the moment, but it's centerforce's flagship model. The one with the counterweights on the pressure plate... The flywheel is stock, but has been milled.

While I have it out of the car still, I plan on tearing into it to check it's overall condition. He's known for driving his cars kind of hard

It's all off of my brothers 92 RS. He recently swapped to a built 700r4 to take the power he's planning on getting, so have everything except the clutch/brake pedal bracket. Even has a new slave cyl. that he never got around to installing. I think the hardest part is gonna be mounting the slave, but I can make a template off his firewall and go from there.

With this motor, I don't plan on seeing anything over 400hp. But I'd prefer to overbuild the trans instead of underbuilding it. I don't like being stranded

 

Replacing the automatic in my car with the T5 really made it fun to drive--and it wasn't too hard to do because I had a parts car, a '91 RS. If you need a pedal assembly or other small parts, F-Body Motorsports at (704) 494-0005 usually has some reasonably priced--they've been good to me. For getting into internal T5 stuff, I like dealing with Tom at TKOPerformance, BegRedK5Blazer.com. He quoted me $700 to upgrade my '91 T5 to handle 450 hp including a complete standard rebuild with some forged parts he recommended.
I like dealing with these people but I bet there're plenty more good folks out there.

 

My T-5 is holding up nicely so far. But I still need a posi.

 

Well, dang it, go get that posi!

 

Thanks for the link, I'll have to check them out

EDIT: I checked out tkoperformance.com, and all they offer is CAGS! and shifters. I also tried the bigredblazer site, and nothing comes up

 

OK--I should proofread better. TKOPerformance is BigRedK5Blazer@aol.com . He's a member of this board, should be listed, and isn't the Corvette parts supplier. I think he's in Delaware. He's in my list of pm's--responds readily but I don't have his phone number.