justin

80 5 speed, OK, this happens in any gear 2800k and above, the shifter will vibrate very severly. If I sit in the driveway, with the car in neutral and rev it with the clutch pedal in, it wont vibrate , if I let the clutch out it will vibrate all the time above 2800k. Clutch is pretty recent, Im thinking TT? I dont know, all I know is this is my daily driver and need to fix it ASAP.
Help

heinrich

Well, most likely is torque tube bearing failure, next likely is driveshaft knuckle.....

heinrich

How about wheels .... swap them.

justin

I forgot to menstion, Ive got the rear wheels off the ground too. I am leaning toward TT, how hard is it to change one?

justin

I forgot to mention, Ive got the rear wheels off the ground too. I am leaning toward TT, how hard is it to change one?

justin

Drive shaft knuckle?

jeff jackson

I would bank on the torque tube bearings...they tend to become "noticeable / obvious"...at certain RPM, due to a combination of driveshaft speed and harmonics. 928 Intl, offers rebuilt tubes on a core exchange basis. The swap is NOT a walk in the park. Figure a couple days if you DIY...and definitely "review several, if not ALL the readily available writeups on Greg Nichols, and other linked sites" to get a feel for what you are getting into....If you thiink the job is beyond the limits of what you want to attempt at home in the garage....at least you will have a good overview of what is involved in this job...and what it should take your chosen repair shop in terms of "time and materials" to complete the job with a pre assembled rebuilt tube supplied by you. (they probably WON'tT like that)...but at least that way they know that YOU know...what you want them to do....and may be less likely to try and "baffle you with bull****"...and rape you on the swap. In my view..if you at all feel competent to do the swap (especially if you have some local 928ers available to lend a hand)...by all means do it yourself. But...if after reviewing the scope of the job, you feel it best left to a professional...make sure he knows....that YOU know...the scope of the job. That will make the pain of the invoice more "bearable"....I hope.

justin

Im guessing TT, like I said above, the vibration comes in at 2800 and dosnt go away untill the rpms drop, it does it in any gear.

EB338

2800K? wow that is seriously wrapped. I can imagine it would vibrate at the very least!

justin

oops, 2800rpm, sorry

justin

Ok guys, I went out and crawled around under the car for a few minutes and I found that the driverside tranny mount bolt was gone. You have one bolt that bolts the mount to the cross member, and another bolt that bolts the mount to the transmission. The bolt that goes from the mount to the tranny is gone on the driverside, could this be my vibration? So right now I only have one mount on the trans, holding it in, I hope this is the root of my problem, BTW does anybody know the size of the bolt I need?
TIA

Garth S

I think the area you describe requires a M12x1.5 x 80mm long bolt. The transverse bolt on the other side is 50mm long, and the two that bolt vertically from the bottom are M12x1.5 x 40mm.
Slide a piece of wire in the hole to determine length .... or verify that the bolt is not broken off inside ..
BTW, M12x1.5 is a fine pitch thread, which Porsche used extensively to annoy folks looking for replacements .... for the coarse M12x1.75 is far more common>

soontobered84

Justin, I may have one of those bolts. Let me know if you need me to bring it to you. The 80mm one.

justin

I called DR @ specialists, he said on the 80 model 5 speed car the driverside bolt is M12x1.50x 50mm. I got an 45mm and a 60mm, going to try the shorter one first. Wish me luck

justin

Well the bolt didnt fix it, still the same, I did notice that if I rev it up to 3k and hold it there in neutral, thw car vibrates very badly, then If I press the clutch pedal in and out quickly the vibration will seem to get a little better and if I keep doing that it will get real bad again. I am not sure if that even makes much sense, but I dont have a clue what to do next. Im starting to think either something is up with the clutch or Torque Tube.