Viscous Coupling Unit (VCU) Failure
SeriousGearbox & TransmissionThe viscous fluid inside the VCU thickens with age, causing it to seize or fail. This can silently destroy the IRD and rear differential. Many owners simply remove the propshaft and run FWD only.
Most affected: All AWD models
Typical symptoms
- •Creaking or groaning at motorway speeds
- •Knocking in reverse
- •Vibrations through drivetrain
What to inspect before you buy
- ✓Propshaft is present and connected
- ✓Listen for drivetrain noise at motorway speed and in reverse
- ✓Check for oil leaks from transfer box