Drivetrain Vibrations - Built Car
Need some help with where to start. No trans codes, pulled pan and see a bit of metal shavings in the bottom. Torque converter bolts are tight. Trans mount is fine. Previous owner said last pass he made down the strip, he felt the 2-3 shift slip, he suspected trans or torque converter.
Car Details:
2000 C5, A4
2800 stall(unkn brand)
line lock
'fully built' trans from a local shop
fully built 383, 200+ shots of nitrous, 10.8 CR, race cam
650-750 whp on the nitrous, 450 ish N/A
I have half a mind to just buy a RPM Stg V trans and converter, but thought I'd see if anyone has any ideas to focus in on the source of the vibration first.
Any help is appreciated.
Trevor





They WILL cause vibrations. That much power and the age of the car,, YEP,,
,, that would be be where I would start.Unless you bent something, the trans should not cause it
Another place to look would be to inspect the rims and tires to see if they are true.
Also do a push pull test on the rear (and front) wheel bearings. Jack up the wheel. Grab the tire at the 12:00/06:00 & 09:00-03:00 positions and push pull and see if there is any SLOP in the bearings. There SHOULD NOT BE ANY!
Let us know what you find.
Bill
I changed my ttube couplers because of vibrations too. Unfortunately I went with poly couplers and now the sound is much more pronounced. But at least I know its safe. If I ever get back in there, its back to rubber.
What about torque converter? Last time I moved the car, it would lockup as soon as I started to roll, killing engine. Went away later. Do you think I could get away with replacing the flexplate, torque converter, and if still issues, then just buy a trans or would I be risking destroying a $1200 torque converter.
I dont suspect tires/wheels, this is more of a RPM than MPH vibration. Vibrates from 0 MPH.
I have RHS pro elite heads on, they are massive, I think I have to pull entire drivetrain to inspect, as there appears to be no room to tilt the rear down. I have a lift and will do a visual check underneath with the car running tonight. It is very hard to tell through the access cover, are those plates that mount the torque converter known to get tweaked? looks a bit undersized for hard bottle launches with slicks.
Last edited by trevorradman; Jan 3, 2014 at 02:59 PM.
Is the vibration felt parked, in neutral, if you rev the engine? (the engine, flywheel, clutch, and driveshaft spin).
Is the vibration felt at certain vehicle speeds?
Is the vibration felt in a specific gear(s)?
Does vehicle speed affect the sound/severity?
Is the vibration felt parked, in neutral, if you rev the engine? (the engine, flywheel, clutch, and driveshaft spin).
Is the vibration felt at certain vehicle speeds?
Is the vibration felt in a specific gear(s)?
Does vehicle speed affect the sound/severity?
Not speed(mph) related.
All gears, intensified greatly by engine load.
At WOT, rpms above 4k vibration chills out all gears(4th assumed, not enough runway to try). Wot Downshift getting on highway, vibration clears up until 2-3 shift, then vibration returns since the rpms dip under 4k.
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Not speed(mph) related.
All gears, intensified greatly by engine load.
At WOT, rpms above 4k vibration chills out all gears(4th assumed, not enough runway to try). Wot Downshift getting on highway, vibration clears up until 2-3 shift, then vibration returns since the rpms dip under 4k.
What about torque converter? Last time I moved the car, it would lockup as soon as I started to roll, killing engine. Went away later. Do you think I could get away with replacing the flexplate, torque converter, and if still issues, then just buy a trans or would I be risking destroying a $1200 torque converter.
I dont suspect tires/wheels, this is more of a RPM than MPH vibration. Vibrates from 0 MPH.
I have RHS pro elite heads on, they are massive, I think I have to pull entire drivetrain to inspect, as there appears to be no room to tilt the rear down. I have a lift and will do a visual check underneath with the car running tonight. It is very hard to tell through the access cover, are those plates that mount the torque converter known to get tweaked? looks a bit undersized for hard bottle launches with slicks.
I also agree on the stock flex plate comment. They are pretty thin. You can get an aftermarket unit to replace it.
I think dropping the trans would be wise.
I know, it's not trivial......I did mine on jack stands. And like a dummy, didn't replace the couplers, which are now vibrating, so I get to do it again......
Ron












