From: Scott C [s.carson3@verizon.net]
Sent: Sunday, April 28, 2002 12:09 AM
To: 928
Subject: [928] Re: MYSTERY vibration....getting close

Give this a shot.....

1. Bring car to speed in 4th gear where vibes are worst.  
2. Change to 5th gear and keep speed steady.
3. With car still in 5th and at speed, depress clutch and let engine 
   speed fall to idle.  
4. With car at idle, clutch depressed and still rolling along....  slide 
   shift lever into 4th very slowly.....  Be sure to observe for
vibrations returning.

This test isolates (for the most part) the TT from the engine.  When doing
the 5th to 4th test, be careful to note the vibration return behavior.
If the vibe appears to "spool up" when engaging into 4th, it is most
likely the TT (don't ask me how I know).

BTW, the TT spins almost all the time regardless of clutch position due to
inertia and parasitic coupling.

Good luck and keep us posted on progress.

Scott
'81 5-sp 119k (with 600 miles on new TT)