964

1989-1994 / Coupe / Targa / Cabriolet / Germany

Common Drivetrain

8. Carrera 4 AWD System Issues

Symptoms

AWD warning light on the dashboard. Unusual handling characteristics (either excessive understeer or oversteer). Grinding or whining from the front differential area. Fluid leaks from the transfer case. ---

Cause

The 964 C4's AWD system was the first all-wheel drive system fitted to a 911, and it is complex. The electronic control unit uses aluminium wiring that corrodes over time, causing intermittent faults. The transfer case and centre differential require periodic fluid changes that are often neglected. Seals in the system harden and leak.

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// More 964 problems

Other known issues

Common Drivetrain

7. Dual-Mass Flywheel Failure

Rattling or chattering noise from the bellhousing area at idle, which disappears when the clutch pedal is depressed. Shudder on clutch engagement, particularly from a standstill. Vibration through the drivetrain at certain RPM ranges.

Common Engine

1. Oil Leaks (Chain Tensioner Housings)

Oil residue on the engine's lower surfaces, oil drips on exhaust components (burning oil smell), oil spots beneath the car.

Common Engine

2. Oil Leaks (Cam Cover Gaskets)

Oil on the cylinder heads and barrel surfaces, burning oil smell from exhaust contact.

Critical Engine

3. Oil Leaks (Cylinder Base Gaskets)

Oil around the cylinder bases, dripping down the engine. In severe cases, oil loss between services.

Minor Engine

4. Timing Chain Tensioner Failure

A rattling noise from the front of the engine on cold start-up (chain slap). Erratic idle. In advanced cases, a metallic rattling that worsens with engine speed.

Minor Engine

5. Engine Bay Fires

Burning oil smell from the rear of the car (this is the warning sign). Smoke from the engine bay.

All 964 problems