Here’s a good check list to troubleshoot weird vibration issues in your 928:

  1. Bad motor mounts (the quick test is to put a floor jack under the oil pan and jack up gently.
    if the vibration is gone, you need mounts. )
  2. Bad transmission mounts (Should have about an inch of clearance between the cross member and the bottom of the Transmission Mounts)
  3.  Bad crankshaft vibration damper
  4. Imbalanced clutch
  5. ┬áMigrated torque tube drive shaft bearings (Front bearing has moved more than 15″)
  6. Torque tube drive shaft bearings not supporting the drive shaft
  7. Collapsed rubber springs torque tube vibration damper
  8. Bent drive shaft

This function has been disabled for 928 BuckeyeLandsharks.