I'm about to pick up an 86 with a crate 350 mated to the stock non WC T5. The vehicle is being sold due to "unknown transmission problems." In the event that the transmission needs to be rebuilt, what am I looking for in terms of making it more agreeable to putting down 350-400 flywheel hp?

I read the T5 FAQ and saw: "1983 to 1987 was the first design, rated at about 280 ft/lbs of torque."

That isn't going to cut it, I'll be making 350+ lb-ft. What can I do NOW to save some face and not have a transmission failure later? Is there a rebuilt kit designed to allow for more power, or is it weak gear material? This car is going going to see a track 1 time in it's life, and after that will be given to someone as a daily driver so with that in mind..

The best advice my buddy had to offer me was "dude forget the T5 swap for an automatic!" All I really heard him say was because I do not touch automatic cars and he only drives autos.

If anybody has anything a bit more helpful than that, I'd appreciate it.

 

Welcome to TGO. A search here is always a good idea. Most members would agree that if you don't hotrod it--power shift, drop the clutch, use slicks, etc--the non-WC will hold up reasonably well. It has for me and I'm running a GM 350ci/330hp HO.

The WC is somewhat stronger.

Since the case in the T-5's is the weak point, trying to beef it up is probably a worthless effort.

JamesC

 

Yeah, sorry about that figured out the search just after posting, but since the 4 threads I was able to locate basically said T56 swap, or better casing I'm going to take some extra steps when rebuilding the transmission.

Thank you for the quick reply, that's basically all I needed to know I'll send the case and most internals to 300 below for cryo treating, that ought to keep in in good shape.

The vehicle will never see a hard launch, or any power shifting. The person who I'm giving the car to when it's done is probably never even going to lay on the gas pedal, so it sounds like trans failures are limited to abuse, and excessive driving enthusiasm.

 

Don't waste your money on cryo treating. Cryo will do nothing(maybe a very slight help) for the case flex which is the death of a T5. If it's not already in need of a gear set, then just get a rebuild kit and don't beat it overly hard. - Any money spent past that is honestly a waste with a T5. It would be much better spent setting it aside for a TKO or a T56.

If you can't clutch dump it or power shift it then a good auto is gonna walk on you. Don't waste money trying to keep a weak trans on life-support.

 

While It would be ideal to swap in a nice 6 speed from a donor car, the goal of this project is just a little competition between two life-long friends. The budgets for the build are surprisingly low, I'll probably make another post about it and re-visit it as progress is made on both vehicles.

 

Ditch the torque arm for a crossmember mounted one.

 

^ definitely helps lower the case flex.

T5's will take more abuse than most people think, but they will all eventually fail when pushed beyond their abilities. - If any gears have already failed, the case is likely already over stressed and will not last as long even after rebuild.

I beat the living crap out of the three T5's I killed in my car. Like I said, a good fresh unit will take it for a while.

 

is there any way, since the vehicle doesn't drive at the moment, to "get an idea" of what the problem is. any visible signs of stress or damage to make note of when looking under the car? ill shift through the gears with the car off to see if they all feel like they engage , but I can't drive it I can only run the engine. I'll let the clutch out in gear once its running to have a listen for the throw out bearing, the feel of the pedal, and the feel of clutch engagement at all but other than that any ideas on what to look for visually on the trans itself?

 

Unless it had a "catastrophic failure" there will be nothing visual from outside the case.