mel_t_vin

Separating the driveshaft from the transmission, via the coupler, is a good suggestion.

A number of folks have rebuilt their own TT. While pulling the shaft and bearings is not too difficult...repositioning the new bearings can be a little challenging. A few years back, Parts Heaven in Hayward, CA, was selling rebuilt TTs. And if not mistaken, 944 Ecology [aka George Beuselinck, PCA 944 guru] was selling rebuilt tubes, as well.

jhowell371

Yeah I missed that part. Timing is set by the computer so it's right . Seems to me that a bent drive shaft would be noticeable over a wide RPM range, from idle speed on up. The shifter in my old 396 Chevy started shaking at all RPMs when it started to chunk off the lining throwing everything out of balance. A bent shaft at the clutch end would be compensated somewhat by the rubber doughnut but I should think the flexing of the doughnut would cause vibration at all speeds. I'd have a careful look at the balance shafts again before pulling the tranny, JMHO.

svx604

The car has a new clutch by Sachs so there's no dougnut to receive any vibration from the torsion axle.

To reiterate, the vibration comes on at a distinct RPM then the shifter starts vibrating like a massage along with noise. I'll double check the balance shafts as I've never done so. Time to learn something new. Fingers crossed.
Off to Clarks Gargage manuals...

snb13

As I said, check if the O2 sensor has come loose. Ask me how I know...
May not be it but it's an easy check and fix if it is.

jhowell371

My 02 sensor came loose too and to started to rattle again when I drove it the other day. After the rattle was misdiagnosed as a heat shield I checked them again and again. I would bang on the exhaust with a rubber mallet and try to run it down every time I was under there but could never find it. It only happened when cold, finally one day it started to run like crap on start up. Thought the 02 sensor was bad went to check the wires and when I touched it, it was loose. Tightened it up and it ran great again. I think I'm going to safety wire it this time.

snb13

Mine came loose a couple times. Finally put some blue thread locker on it. No problems since. But it'll drive you crazy looking for it.

snb13

Any update on this?

svx604

CONFIRMED balance belt was off sync, by 1 tooth on top and 180degrees on bottom.
I've fixed it and learned something new. Engine is very smooth and it feels like I have a larger powerband esp shifting from 1->2 going uphill. Thanks all for your help.