Holden Commodore Gearbox & Transmission Problems

The biggest problem with this model of Commodore was it’s V6 engine and that unit’s propensity to suffer stretched timing chains. Cars without a full service history will be the worst offenders, but even a car with a perfect maintenance track record can still require new timing chains. However, this usually occurs long before 200,000kmk have been clocked up, so it would be very interesting to see if the car you’re looking at has, indeed, had this repair made by a previous owner. Of course, even if the timing chain has been replaced, that’s no guarantee that the problem won’t occur again. There’s also a suspicion that the three-litre version of the Holden V6 was a bit underpowered and needed to be driven hard everywhere; a situation that didn’t help timing-chain wear at all.

Other problems with the VE Commodore generally include some electrical problems that are surfacing with age, particularly camshaft-position sensors, a build-up of carbon on the intake valves which can cause rough running and poor economy, oil leaks and leaks from the cooling system. That said, if you can find a good one with an engine that has had new timing chains, the VE wagon represents a lot of car for not much money these days.
 

This is not an unknown problem with Holden’s Alloytech V6 engine and can often be traced back to a damaged gasket for the thermostat housing which is located at the rear of the engine block. And you’re right, to change this gasket which costs just a few dollars, involves removing the exhaust and transmission. The best advice is to have the thermostat itself changed while all this work is being done, as it will save you going through it all again if the thermostat ever fails (and they have been known to).

But definitely have it checked out as coolant leaks never fix themselves and a small leak today could easily be a big leak tomorrow, leaving you stranded with an overheating engine. Meantime, you might be lucky and discover that the leak is not from the thermostat housing at all. These engines are also prone to coolant leaks from a pair of O-rings at the front of the cylinder heads which can allow coolant to leak through the valley and out the back over the transmission tunnel, making you think the leak is from the rear of the V6. Don’t rule out the water pump as a source of leaks, either. The trade seems to think about 100,000km is the lifespan for an Alloytech V6’s water pump.

It all depends on what engine is fitted to your car, Karen, as Holden used a range of gearboxes in this series of Commodores. If your car is the base-model version (the Omega) it will be fitted with a four-speed automatic (code-named the 4L60E). If your car is an SV6, it will have either a five-speed automatic (5L40E) or a six-speed manual (the Aisin D173/AY6 unit). If your car is a V8 Commodore, it will have either the six-speed automatic (6L80) or a six-speed manual (Tremec T56) fitted.

Of all those transmission options, the five-speed automatic was the odd one out as it was only used from the launch of the VE until the first facelift in 2008 when it was replaced by a six-speed automatic.

I can’t see why not, Peter. The 1996 and 1999 are more or less identical cars so there should be a high degree of interchangeability. While manual versions of the Commodore Ute form this era did, indeed, change gearbox types as the years progressed, the automatic version stuck with the same unit, so the gearbox and all its ancillary bits and pieces should be a straight swap.

And how good is a ute with a bench seat for three and a column-shift? Car makers should revisit this layout as it makes so much sense.

The standard differential on this vehicle was a non-LSD (non-limited-slip) unit with a final-drive ratio of 3.08:1. Some owners changed the gears in the diff for more acceleration, although this was more commonly done in V8 models where owners were chasing performance at the expense of a little fuel economy.

If you’re in doubt, you can put the car on a hoist, mark a spot on the driveshaft and then turn the rear wheel a full revolution. By counting the number of times the driveshaft rotates during that process, you’ll know the ratio. In this case, one full rotation of the rear wheel should equal 3.08 rotations of the driveshaft.

There were a number of owners reporting problems with the torque convertor shuddering back in 2012 and requiring the convertor to be changed.

The demand for manual gearboxes is so low today that it’s not worth car companies doing all the compliance work needed when they know they would only sell a handful of cars. You might have to loo at something like a Holden Commodore.

Given that the warranty is going to expire in the coming year I would press your dealer to fix the problems that are causing you concern. They appear to have fixed the leaking radiator, but the air-conditioning and gearbox issues should be fixed. If the dealer cannot, or is unwilling to fix them escalate the problem by talking directly to Holden's customer service.

Yes, it can be rebuilt or replaced and an automatic transmission specialist would be able to do that for you. Cost for the job would be around $2000 to rebuild or replace the transmission on a changeover basis.

You certainly haven’t had a good run with it. I have heard of transmissions being replaced, but not many, and I haven’t heard of widespread trouble with the other issues you have had.