Excessive Drivetrain Vibration
From E34 Addicts
This section will cover basic drive vibration culprits under normal and hard driving conditions.
Stage 1 Inspection
Slight motor / shifter movement / clunk in the rear
- Motor mounts
- Transmission mounts
- Differential mounts
- Shifter bushing
Stage 2 Inspection
Slight motor movement that increases severely under hard acceleration. You might feel motor shift when doing hard pull if pedal is cable driven (inspect the cable for over stretching/failure points). Often the shifter will move to a side (aggressively) as RPM's climb.
Must perform stage 1 inspection.
- Misfire, 02 sensors, spark plugs, DME, Check for intake leaks Check MAF (Mass Air Flow Sensor)
- Missing blades on radiator fan
- Shot fan clutch (seized/play)
- Shot water pump bearing Water Pump
- Shot harmonic balancer Harmonic Balancer
Stage 3 Inspection
Improper timing will make your car sound like a old truck, high engine vibration on/off at idle.
Must perform stage 1 and stage 2 inspections.
- Improper timing Engine Timing
- Improperly surfaced fly wheel / out of spec
- Low compression Compression Test
