rshanholtz

In my 86' 951, I have a rebuilt 89' 951 engine, with all new suspension, new engine mounts (OEM), new axels, new tires, new transmount (OEM) and rebuilt 89' LSD Tranny. I have developed a bad vibration and noise when in any gear past near or over 3k RPMS and i come off of the accelrator but remain in gear. As soon as I put the clutch in, the sound and vibration goe away. I hear and feel it mostly on decel, as soon as clutch goes in, problem goes away. I also hear/feel it when in 2nd gear and climbing a hill at low speed. I am thinking it is a bad torque tube as almost everything else is new. Any suggestions?

951Saga

Try sliding the coupler off the torque tube shaft to the trans shaft, removing the trans as a possibility. Run the motor to see if it behaves the same.

-Jason

buxton

Do you get a vibration through the shifter? When you are stopped and rev the engine with the clutch depressed, does it vibrate? How about when the clutch is out?

rshanholtz

I get vibration through the shifter always but is worse when in gear under load.

buxton

Sounds like the torque tube to me. I spent close to a year chasing down the same type of symptoms you had. Turned out to be the tt. Do a search on driveline vibration and hopefully you can find the thread that I started. It is a good size job and one that you may want to do the clutch, rear main seal, etc.... while your in there. If you have any questions you can pm me and I may be able to help with a final diagnosis and tips on repl. the tt. I just did it about than 2 months ago.

rshanholtz

I ordered a remanufactured TT from Porsche- I know, way too expensive could have replaced the bearings etc, but this is something you only want to do once... With the TT out, spinning the tube manually generates a loud noise at the rear and a little at the front of the tube. Thanks for everyone's help in diagnosing.
While in there, I also replaced shift rod, shift lever, some wear items, and protective sheeve on shift rod. Mine was missing from car.

944S2IFISH2

If you don't mind... How much did Porsche charge for the TT? Do they require a core?