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Commodore (VN-VZ) / HSV

1988-2006 / Sedan / Estate / Australia

All Commodore (VN-VZ) / HSV problems All workshop issues
Common Transmission

Manual Gearbox Synchro Wear

Symptoms

Grinding or crunching when shifting into 2nd or 3rd gear, especially on cold mornings or when shifting quickly.

Cause

Synchro rings wear with age and mileage. The T56 6-speed manual (VT II onwards) is generally robust, but 2nd-gear synchro wear is the most common complaint. Aggressive downshifting accelerates wear.

Fix

Synchro replacement requires the gearbox to be removed and partially disassembled.

Budget $800-1,500 for a synchro rebuild.

Using quality gearbox oil (Motul or Penrite) and changing it every 40,000 km helps prevent premature wear.

Cost mentioned in fix
Budget $800-1,500 for a

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Other known issues

Common Transmission

4L60-E Automatic Issues

Harsh 1-2 shift, delayed engagement from Park to Drive, slipping under hard acceleration, shudder during torque converter lockup.
Common Engine, V6 (Buick/Ecotec 3.8L, VN-VY)

Intake Manifold Gasket Leak

Coolant leak at the junction of the intake manifold and cylinder heads. May present as coolant loss without a visible external leak (coolant enters the intake ports), or as a coolant stain on the side of the engine. Engine may run rough or misfire if coolant enters the combustion chamber.
Critical Engine, V6 (Buick/Ecotec 3.8L, VN-VY)

Harmonic Balancer Failure (Ecotec, VS onwards)

A wobbling pulley on the front of the crankshaft. Knocking or rattling noise from the front of the engine. The drive belt may track poorly or come off.
Common Engine, V6 (Buick/Ecotec 3.8L, VN-VY)

Supercharger Bypass Valve Failure (L67 supercharged V6)

Loss of boost, rattling from the supercharger, reduced performance. The supercharger may make a whining noise that changes with the valve's operation.
Critical Engine, V6 (Alloytec 3.6L, VZ)

Timing Chain and Guide Failure

Rattling noise on cold start that may persist after warm-up. Check engine light with codes related to camshaft timing. Rough idle, misfiring, loss of power. In severe cases, the engine won't start or runs extremely poorly.
Critical Engine, V6 (Alloytec 3.6L, VZ)

Oil Leaks from Timing Cover

Oil weeping or dripping from the front of the engine, behind the harmonic balancer area.
View all 20 Commodore (VN-VZ) / HSV problems