Hey guys, I have a bit of a problem. Yesterday i went out to my local track to do some test launches on my 96 Z. Thing is that after a couple of launches it was fine, but on my final launch i accelerated from 1st to 2nd shifting in to second way before hitting rev limiter, but as soon as it hit 2nd i heard this loud thunk at the back of my car, felt like the rear right had fallen into a pot hole or something, i checked and everything was alright, so as i was driving home i had a go at the throttle again this time in D and as soon as the car downshifted it thunked again in the rear, and i can feel a slight vibration while holding onto the shifter...any ideas to what it might be? During normal driving conditions it shifts fine through all gears, but on hard accelerations it feels like it wants to come apart.

 

Lift your car up and jack up on the transmission a bit (use a block of wood to cushion it) or use a big pry bar to lift it up. Look at the transmission mount...if you can see it coming apart while you have pressure on the transmission, it's time for a new one.

 

Cheap part to replace ($8-20) and only takes a few min with a jack and socket wrench.
The stock rubber ones break all the time.
Replacement 1LE are a little tougher to break, and the aftermarket
polyurathane ones are even stronger but tend to transfer more vibration to
the chassis (IE you will feel it).

I've been happy with Polyurathane mounts in two of my Fbodies.

 

Tranny mount or U joint