Excessive Drivetrain Vibration

From BMW E34 Encyclopedia

This section will cover fundamental drive vibration culprits under normal and hard driving conditions.

Stage 1 Inspection[edit]

Slight movement of the engine and shifter. Clunk in the rear.

  • Engine mounts
  • Transmission mounts
  • Differential mounts
  • Shifter bushing

Stage 2 Inspection[edit]

The engine movement increases rapidly under hard acceleration. You might feel the engine shift during hard pulls or downshifts if the pedal is cable driven (inspect the cable for over stretching/failure points). Often the shifter will aggressively pull to a side as RPM's climb.

  • General misfire. Check the 02 sensors, coils, and spark plugs
  • Check the system for vacuum leaks
  • Check the Mass Air Flow Sensor (MAF)
  • Missing blades on the radiator fan
  • Shot fan clutch. Either seized or has excessive play
  • Shot water pump bearing
  • Failed harmonic balancer
  • Check the DME/ECU by swapping in a known good unit

Stage 3 Inspection[edit]

Improper engine timing will make your car sound and vibrate like an old truck.

  • Improper timing
  • Improperly surfaced flywheel
  • Lightweight flywheel that is severely out of specification
  • Low compression