Inliners International Forums General Discussion Drive Train I have a Vibration from somewhere, help!

Got a '51 Chevy 2 dr sedan with 235 inline 6 and original 3 speed manual. I replaced the clutch and 3.55 gears in the rear and the timing chain in the motor went up and a shop in Ohio pulled the motor and went through it all to fix it. Ever since its had a bad vibration from 50-55mph and when I push in the clutch, its still there and going slower than 50, you can't feel it but above about 60 you can't feel it either, just withing that 10mph interval. You mainly feel it in the back seat. Everything's tight, wheels balanced, replaced motor mounts.

I was told that it could be something with the pressure plate? Something like not put in right or bad somehow. Is this a possibility???

And I could remember there were suppose to be shims under the trans mount (or above?). Is this true too or was I thinking of something else? There are no shims in mine, could this cause the vibration? Any Help is greatly appreicated, thanks.

Ryan Washington
www.RyansCustoms.com

It could be unbalance in the drive shaft.When you did the rear did you replace any part of the drive shaft?

The driveshaft may be out of phase. If you've checked everything else, and your tires are balanced, then you might want to remove the driveshaft and reinstall it 180 degrees opposite. Just a thought. John

Recheck the rear tires for balancing. When you feel it in the seat that is usually the problem.
Good luck
D.D.

A worn drive shaft bushing in the torque tube is another possibility.

Well here's what I did today, jacked it up, pulled the tires and drums off and brought it up to the speed it usually vibrates, and it still did. This eliminates the wheels. So I removed the Clutch cover and ran it and at idle while in 1st gear, I can see up around the throwout bearing where the input shaft goes into the pressure plate, the pressure plate wobbled around and around, but just around the center of those springs. Then at the speed it vibrates with myself under there, I could see the entire clutch/flywheel/pressureplate assembly ovaling around and around, like a small wobble but enough to notice it and around the imput shaft on the trans where it goes through the pressure plate again, I can really see where it is out of whack or something where it wobbles like crazy. Could this be the Pilot bearing gone bad?? I dont ever remember replacing it, only the clutch and pressure plate and had the flywheel turned. Thanks

Ryan Washington
www.RyansCustoms.com

what do u mean u pulled the tires and drums off? u mean u drove around on the spindels? WTF? sounds like a dangerous way to find the problem, but i'm glad u seen it, although i cant help u out...sorry.

Ryan,If I were you I would drop the tranny and using a good quality centering tool remount the clutch and pressure plate.It's more work than you want I'm sure, but at least you'll be able to check everything including the throwout bearing,crank pilot,bolt torque and general condition of it all.