TF 904 Vibration at Speed

[BlueCuda]

Am getting a pretty bad driveline vibration beginning at 4800 rpm in 3rd becoming a tooth rattler at 5200 (about 110 mph). Lifting and slowing to 50-60 mph or so and shifting to neutral brings it back (doubles the clutch pack rpm). Back to third, smooth.

Any ideas?

Thanks!
Mike

Am getting a pretty bad driveline vibration beginning at 4800 rpm in 3rd becoming a tooth rattler at 5200 (about 110 mph). Lifting and slowing to 50-60 mph or so and shifting to neutral brings it back (doubles the clutch pack rpm). Back to third, smooth.

Any ideas?

Thanks!
Mike

Mike,
This sounds like you have a bushing going bad some were in the trans. i would drop the drive shaft and check that bushing 1st. If nothing in there is i would say to check that balance of the drive shaft. I would not think anything in the trans could be loose enough to shake the car.

Thanks

Russ

[BlueCuda]

Thanks for the info, Russ.

I've thought the driveshaft might be "Jump Roping" as it is the original thought u joints have been replaced a few times.

What led me to the trans was that the vibration intensifies when coasting in neutral such as if at the end of a run I clicked it into neutral to let the engine idle or shut down for a plug check. I never do that anymore and never did plug check as I know that would starve the trans for lubrication with the pump not being turned by the engine.

I have plans for a new shaft and will pull the trans down to look for worn bushings. Those are original as well!

Thanks, again!
Mike