Ok I had the aluminum d/s balanced just for kicks and giggles/tried it both
ways (180 degrees) had the tires/rims checked and I still have vibration
starting at about 80 mph and it feels like the car is going to come apart at
115! Where is the next place I should look for the problem? Also, just as
a reminder this was a swap from an A4 to M6 in a '95 T/A. When the A4 was in there with
the steel d/s it ran perfectly at any speed.


Thanks in advance!

 

anyone?

 

When is the last time you changed your shocks?

It could also be your U-joints.

 

vibration could be many things. Where do you feel it? in the seat or in the steering wheel? The steering wheel is front end the seat or butt vib is in the rear and whole car could be trans, DS or mounts. How was your flywheel?? That could be real bad. Also is the trans perfectly aligned with the rear?

Just taking shots here. good luck.

I also am considering making the swap to M6.

 

this may be a dumb question, because its been a long time since i have had my car apart and i work on all different cars, but could you have put the flywheel on in the wrong spot? meaning rotated it causing the engine to be out of balance? i forget if the flywheels are zero balance or not. i think your problem lies in your flywheel/clutch/trans because you said the vibration came when you did the switch, right?

michael

 

Then the vibration would be at high RPM in any gear and any speed. Rev the car in neutral, that will tell you if the Flywheel is out of balance.

 

EXACTLY, pop the clutch in the real bad vibration range and if it quits with the clutch in, it's probably in the engine/flywheel assembly and if it continues with the clutch in, it's in the drivetrain somewhere. If it still vibrates with the clutch in I would guess the u-joints. If it quits when the clutch is in, it almost has to be the flywheel/clutch assembly

 

Check your torque arm mount and tranny mount to see if either is busted, if their fine I'd move on and check the u joints if the problem still persists, then do the flywheel last because it'll be the hardest.

 

I just went through the same thing, altho, mine was an m6 from day one.
Balanced everything!!!
Touned out to be the rear tires, they balanced out, but still caused high speed vivration.
Those balancing machines must not be good for 80 or above speeds

Replaced tires... problem went away. :rollin

Michael

 

Thanks for the good advice guys! I know my u joints are ok and presume the d/s and tires are ok since they were both checked. I was leaning towards the tail shaft bushing but now am thinking its the flywheel. I'll try out that test where you get it up to speed that it vibrates and push in the clutch. I think I've done that before and it goes away. Thanks again!