Hello i just recently did a 5 speed swap to a t5 in my 86 z28. I payed a transmission shop to swap the tranny and i did the rest of the work. Everything works and the car drives well but when u really put your foot down in 1st or 2nd the shifter jumps about 3 inches up. Did they forget a mount or is there something else that could be wrong? thanks Dave

 

Yup; the trans mount is either broken or missing, or the bolts are loose or missing.

 

Thanks but im sure they would have noticed if it was broken. If i look down the shift hole in my parts car(86 firebird) i can see a bracket that looks like something slides into it and if i grab it it feels like it runs to the back of the car. i cant get underneath due to an abundance of snow. Is that the torque arm? would that cause my problem? Thanks Dave

 

Yes, that is the torque arm. And yes, it is causing your problem(in a sense). When you punch the throttle, the rear wheels try to spin to drive the car forwards(down relative to the front of the car or counter-clockwise if you're looking from the side). This forces the differential to want to rotate in the opposite direction of the wheels(Up, or clockwise). The torque arm is bolted to the front of the differential and the rear of the transmission. When the differential tries to rotate, it lifts the front of the torque arm which tries to lift the rear of the transmission where the shifter is. If the transmission mount is loose or broken then the entire tail end of the transmission lifts up a few inches.

You need to get that transmission mount fixed before you destroy your transmission. T5's aren't all that strong to begin with, and having the torque arm lifting it that far off the crossmember is not good for a lot of parts, but will destroy the tailshaft of a T5 in short order. Once it's fixed you'll also notice an improvement in how quickly the car responds to your right foot since the motion of the wheels will be directed towards propelling the car forward, not lifting the torque arm.

 

I beleive the T5 torque arm bushing and clamshell are different from the 700r4. Best bet if you don't have one is the classifieds, ebay, or even Hawk's Thirdgen. They'll be a little higher, but you'll get the right part, the right hardware, and it shouldn't take too long.

 

if the connection on the rear end is the same i have the one from my parts car it will bolt on the tranny cuz it was on there before. Thanks for the advice. Just curious how much would an aftermarket one be and would it be worth the upgrade? Thanks Dave

 

An aftermarket polyurethane tranmission mount is around $15-20 seems to be a bit stronger than the factory one. I've been running one on my Camaro since I got it and haven't had any problems. A friend of mine owned several thirdgens right out of high school, the first one having a T5. He went through 3 or 4 OEM mounts in 2 years before he finally switched to an aftermarket poly one. That was the last one he put in. He was pretty hard on that car though. He destroyed 2 T5's in it, both behind a stock 2.8L V6.

There were a couple different transmission mount/crossmember setups used throughout the thirdgen run. They are all interchangeable though, but you have to swap over the entire crossmember and mount to do it.