User Guide
5 DMF failure diagnoses
Summary of general inspections in the case of noise
LuK Service Info provides additional information for a
reliable diagnosis.
Noise when starting:
• Battery voltage too low
• Dirty/worn starter
• Worn/defective engine bearings
Hum:
• Worn/defective tyres, suspension, exhaust unit, engine
and/or gearbox bearings
Noise when changing gear or varying load, engagement click:
• Drive train (gearwheel backlash, play on articulated drive
sha and universal joint sha, dierential and compen-
sating gears)
The following summary points out possible fault sources
which may be erroneously attributed to a defective DMF.
Only aer an exhaustive inspection should a decision be
made to replace the DMF.
Rattle when starting/stopping, idling, accelerating and/or
in overrun:
• No gearbox oil, too little or incorrect gearbox oil
• Defective pilot bearing (angular/parallel misalignment
between engine and gearbox)
• Gearbox input sha bearing worn/defective
Noise when starting/stopping, idling:
• Worn/defective engine bearings
• Accessory drive (decoupled belt pulley)
• Engine management (throttle flap)
. Noise