Vauxhall official advice is that the Automatic Transmission Fluid (ATF) is for the life of the car and does not need to be changed, unless operating under ‘extreme conditions’ such as taxi, police car, or when towing, in which case the ATF should be replaced every 60,000 miles.
Our advice is that the ATF needs to be changed every 40,000 to 60,000 miles regardless. The experience form members here who changed the ATF is that almost always it produces a smoother better-shifting gearbox.
Also, problems with the automatic gearbox are rare, and there have been many cases where boxes were doomed by the garage (or people bought cars and very low price because the auto box was thought to be knackered), and the box was miraculously revived by a simple ATF and filter change.
The standard method of changing the ATF is by dropping both sumps, cleaning them, putting them back and refilling with fresh ATF to Dexron III. The filter should be cleaned and examined for any damage, if damaged it needs to be replaced. Unfortunately the filter is quite expensive from Vx, it is around £60 Trade, more if bought at Retail price – so the general advice is that unless you can get one on the cheap from motor factors then there is no need to replace it if it is not damaged.
As for quantities, the total system capacity is nearly 10L including the torque converter and the oil cooler (which is incorporated into the radiator at the front of the car). If dropping the two sumps, you will get only around 4.5L out. Ideally you’d want to change the entire 10L, but there is no official way of doing this – apparently you could disconnect the oil cooler pipes (though this is fiddly) and feed new ATF from one side while letting the old ATF drip out through the other pipe – pretty much in the same way you would bleed the brakes to change the brake fluid. But I am not sure if anyone here actually tried this, as far as I know most people here simply change the fluid in the sumps. Again, this may not ideal, but even changing just half the ATF will still help revitalise it so the recommendation is that at the very least you should perform this basic task.
One other point is regarding the gaskets for the two sumps – the set costs around £15 Trade from Vx, but Mark DTM recommends that no gaskets are used and instead a film of Locktite liquid gasket should be applied – this apparently provides better seal than the gaskets.
And last, you could shorten the process by using a 500cc syringe with a long tube, and replace the ATF without dropping the sumps – the downsides though are that you will only be able to change the fluid on one sump using this method (the one with the filling hole in it) but not both sumps, you will not be able to remove any sludge that may have accumulated at the bottom of the sumps, and you will not be able to inspect or clean the filter. So this is only a solution if you really need to change the ATF in a hurry, and only a temporary one at that.
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Topic: Auto gearbox filter (Read 1570 times)