Redbirds

I have a 2002 Trans Am A4 that was converted to M6.

Mechanic working on it says that it vibrates with increasing RPM. He sent out the driveshaft to get balanced by a high speed balancer in Ohio (goes up to like 9000 RPM or something). I haven't confirmed but I believe even after getting it back and checking the angles there's still a vibration.

He's also tried clocking it at different positions too.

I haven't driven it myself to know what the vibration feels like, but as an automatic it never vibrated (not that it was at high RPMs often since it shifts earlier than I would on a manual).

The car is lowered with an adjustable PHB- I've seen some people bring this up in other threads with trans jobs, so I'm not sure how much of an impact this would have.

I guess I'm just look for other rabbits to chase at this point before we start slinging big dollars to fix it. Does anyone have any ideas?

BALLSS

did he put on a stock FW?

You may need to balance the FW = to what the flex plate was

Redbirds

Ahhh. He did put on an Aluminum FW at some point because I think he had one laying around or it was given to him (it was no charge to me). I wonder...

I do need more details from him but that's a whole 'nother story.

jmm98LS1

iTrader: (28)

If the vibration follows engine rpm, the cause is usually in front of the transmission....in your case probably in the clutch stack. If the vibration follows vehicle speed, the cause is usually behind the clutch stack....trans internals, drive shaft, suspension, tires etc etc

BALLSS

So you are confident the DL angle is within spec?
Was the PHB on the car when it was an A4?
Were there shims between A4 and its rear mount and if so were they put between T56 and rear mount? (pic)


does the motor vibrate just revving or is the vibration correspond to the speed of the car moving?

if vibrate when just revving motor...I would focus on the FW balance