Hey guys i have a problem with my TA. Its a 1986 Trans AM. I have a 94 LT1,4l60e trans and 9 inch rear. When im driving around and the car is in 3rd gear and i step on the gas. The car makes a clunk sounds like something is banging but there are no marks under the car and the tranny mount isnt ripped. Also when the car revs past 4500 rpm there is a horrible vibration in the car until it shifts gears. I have had the driveshaft and tires balanced, no difference. I think it might be caused due to a driveshaft angle misalignment. Has anyone had anything like this happen to them? Or does anyone know of a driveline specalist that might be able to fix this problem?
Thanks
Tom

 

Maybe one of the motor mounts are ripped?

 

does it vibrate just reving, or only when the vehicle is in motion, if it vibrates while sitting still and reving the engine, the problem is in the engine.

 

Hey quickstyle, thanks for the reply, no it only happens when the car is in drive in every gear while im driving.but if i shift it to neutrel while im driving it goes away.
Tom

 

its definatly somewhere between the flywheel, and transmission, seeing as it stops vibrating when the engine is disconnected from the transmission. also, is it an auto or manuel.

 

Its a 1994 auto 4l60e trans.
Tom

 

I'm no expert, but maybe it has something to do with your driveshaft being out of balance. It could be the cause, especially at higher engine speeds. Other than that, tranny problem maybe?

 

could be driveshaft out of alignment also could be driveline angle out of adjustment .....

 

he said it wont vibrate when its in nuetral, which makes the driveshaft still spinning, which makes it related to the front of the transmission or TC or flexplate

 

Uh, does the driveshaft spin in neutral? The last time I checked the car does not move when it's in neutral and I"m pretty sure that the rear end is not the thing that prevents it from moving.

 

when the car is in motion, lets say 80mph, you put it in nuetral and coast down the road at 80mph, yes the drive shaft still moves, as it is connected to the rear end, and the rear end is in motion.

 

What does the tranny crossmember look like?
I know in my 82, mine looked like this, and the bushing between the two halves on the driver's side had broken and was completely gone, and I had the same problem. The transmission was turning and thumping the top half against the bottom half.
As soon as i put it into neutral, it would stop

 

the tranny crossmember in there now is a spohn custom made piece. I had his torque arm too. IT was made wrong and it was a piece of crap, i think he messed up when he made the crossmember too because i think that it is the problem. I think that the angle on it is wrong. I am going to put my stock tranny cross memebr back in and stock torque arm this weekend and see if the vibe goes away. If it does then i know the crossmemebers tranny mounting angle is off and its causing the vibration, if it doesnt go away then im guessing i have a problem with my tranny or rear end. but I dont think so because they are both new less than 10,000 miles on them.

 

One thing that no one ever seems to remember is that the driveshaft angle has to be correct in a Horizontal plane as well as a Vertical plane.

When you remove a transmission crossmember you should make a mark it's position so that it goes back in EXACTLY the same position. During a clutch swap, we were not carefull enough with this. The crossmember was out only 3\8" from it's original horizontal position, but that was enough to cause a HUGE driveline vibration. Loosenning the bolts and realigning the crossmember solved the problem in about 5 minutes.

If you change crossmember types, mark a couple of reference points on the chassis before removing things. Take a measurement from these points to the driveshaft to make sure that you can get the driveshaft back to it's correct position in a Horizontal plane.

Bit late now....but can you take some measurements off of a friends car to establish a baseline? ( One that does not vibrate hopefully LOL )