Auto Fluid change

[nikgallagher]

All the threads I have found regarding renewing auto trans fluid seem to indicate that additional pipework and 'flushing' of the system is required. Is it not possible to just drain the old fluid out (assuming there is a drain plug), and then add new stuff in through the dipstick, similar to an engine oil change? Fluid seems ok now, but was thinking about doing a change at the 100k service, along with a million other things!

[Wobbly Dave]

It is entirely possible to drain most of the oil out through the gearbox sump plug.

if you jack the car up and secure with an axel stand (God knows I don't want a flat Nik on my conscience ) and skoot under the car from the front at the gearbox side - you will first see the cooler feed pipe coming out forwards. Run you hand down the inner edge of the gearbox. The sump plug is that big nut about 1/2 way along.

Run the car and get it up to operating temp.
Get a bowl or suitable receptical and undo the sump plug. Use rags and cardboard in the area to stop mess - it comes out at a fair pace and it will be hot. Next undo the outbound cooler feedpipe. This will remove about 50 - 80% of the fluid. The AT should hold 7 litres.

When all the drips have stopped, reconnect the pipe - make sure you don't loose the O ring on it and do up the GB sump plug.

Open the bonnet and remove the air feed to the air box. Pull out the yellow dipstick. Refill the box with Dextron III ATF, by pouring it through the dipstick tube. A redex bottle with the bottom cut off makes an ideal funnel for this job. Buy the redex and stick that in your fuel tank for a giggle. Cut the bottom of the empty bottle off. Don't wash it out with WATER whatever you do!!

Stick in a couple of litres at a time until you can get a good idea on the dipstick that you have filled the box to the correct level. Check the level with the engine running. Repeat the filling process until you have the correct level.

Turn the Engine off.

You can just leave it at that, if you want to get serious about the change the next steps require you to flush in and out 2 litres at a time until the stuff coming out is the same colour as the stuff coming out.
To do this remove the battery and the tray it sits on. You may have a motor for the headlight wash - put this to one side. You will see a pipe coming from the stock cooler into the top of the box.
Disconnect this pipe with a spanner at the gearbox end. They can be stiff so use penetrating oil to loosen then - gently but firmly being the key.
More Blue Peter DIY - cut the top off a 2 litre plastic pop bottle.
Nestle said receptical into the area between the cooler and the box. Put the end of the return feedline into the pop bottle.
Rest the battery on top of the inner wing and reconnect the terminals.
Turn the engine on - best if you have a mate to help with this bit.
Watch the bottle fill up. When you have about a litre coming out then stop.
Fill the box with fresh ATF through the dipstick tube with your home made funnel. Try to put back the same as came out. Repeat until the colour coming out is the same. It took me about 12 litres to do this.

The idea of using extra tubing on the return feedline is to give you more room to work with. The pop bottle method means you don't have to.

If you want me to help to do it then my time/efforts are free - but alas petrol isnt.

[nikgallagher]

Cheers for another thorough reply Dave! Why do you have to have the engine running when you're filling it back up though? And won't this be a bad idea with a gearbox empty of fluid? Have only seen ATF in 1 litre bottles too, so imagine it will be an expensive 7 litres...

[Wobbly Dave]

To refine my instructions - what I should have said is you fill the box witht eh engine off and check the levels with the engine running.

ATF is expensive and a flush change will cost about £30 - £50 in ATF.