Hello, after making sure my Elite is maintained to the highest of standards using some of the guides on here, I thought I'd make this little 'how-to' to help others.
I set about changing my ATF as I strongly suspected it hadn't ever been changed, and was right! Benefits from doing this job could include longer gear box life, possible increased m.p.g., quieter and smoother box. Mine is the AR35 box, I don't know how similar the AR25 box is, but hopefully this can be used for that box aswell.
Tools required:
Chocks, axle stands, socket set, hammer, oil tray (old washing up bowl), rags/newspaper/old carpet, jack, torque wrench. Optional - barrier cream, knife, wood chisel, sand/emery paper. I also bought a B&Q easy watering 5 litre pressure sprayer (in a nice fetching green shade), to get the new fluid in. It was ideal for the job, cost £16, and can be cleaned out and used in the garden. (B&Q code 0000003643402)
Parts required:
N209 27 01 filter, 4L30E, AR25, Vauxhall 44mm £21.01
N209 25 02 rear pan gasket, GM 4L30E, Vauxhall £5.10
N209 25 01 front pan gasket, GM 4L30E, Vauxhall £3.76
You will need to double check part numbers and prices yourself through JPAT as I lifted this info from another post. I got my parts from Dave Kember at A.B.S. for £40 delivered, which was quick and easy.
Dexron 3 ATF. From dry I believe the box holds 8.8 litres. This method got about 5.5 litres out. I purchased 9.1 litres (2 x 4.55) £39 delivered.
The job:
1. Take car for a short drive to warm the ATF so it comes out more readily.
2. Park on flat, level, firm ground. Handbrake on, jack and stand drivers side, chock the wheels. Use non slip interface between stands and car (such as old carpet patch, wood etc), so there is no metal on metal and less chance of slipping and you becoming a pancake. When jacking the car, I find it best to select 'neutral', because when the car is jacked I find it rolls onto the 'park' peg, then when you select another position it gives a big thud when the peg is released which doesn't sound healthy. Only do this though if your handbrake is upto the job.
3. There is the potential to make alot of mess, and ATF isn't DKNY, so use old carpet/newspaper/rags to protect ground, and gloves/barrier cream to protect you so you don't stink! Haha!
4. Position oil tray/old washing up bowl under level plug. This is situated half way up the drivers side of the rear (biggest) sump. You'll know it when you see it, it's not a drain plug hence not at the lowest point. Slacken level plug (13mm IIRC), don't fully remove, let ATF flow out into your container (not a great deal at this point). Be very careful as you are working near the cat. converters which will be quite hot even after your short drive. Hand tight level plug - to avoid spillage when sump comes off.
5. Undo (16 x 10mm IIRC) bolts with washers from large sump and place to one side. After removing the bolts my sump still wouldn't come off. Here is the awkward bit! Carefully support sump whilst 'encouraging' it to come off with a hammer, and avoiding spilling ATF everywhere! I used a few loosely fitted bolts to help support it. Don't hit it too hard you don't want to damage it! Drain ATF into container. Repeat for small sump. There is an ATF cooler pipe bracket next to one of the sumps that one of the bolts go through. Once all the bolts are out just move it round so the sump comes off easily.
6. Once my sumps were off I noticed half the gaskets were baked to the sump and the rest were still on the car! I used a Stanley knife blade, wood chisel, rag and sandpaper to get it off the car, it was a little awkward. When doing this be very careful as the blade comes very near to the wires and internal workings of box, which you do not want to damage! Nor do you want to get bits of gasket/particles inside!
7. Remove remaining baked on gaskets from sump pans away from car (and preferably in a warm garage!) Clean out sumps and degrease (not vitally important - but I only got 5.5 litres of ATF out on this job so every little helps! Check for metal bits in the bottom.
8. At this point you could consider removing/flushing cooler pipes to get more ATF out - I, however, didn't.
9. Remove the filter (A.K.A. fluid screen) which will present itself after you take the large sump off (3 bolts). With container under here still, and engine off, move the gear gear selector through the range to encourage more ATF out. I have heard you can clean and re use/save the filter. I'll be doing that to mine later! Wipe off old ATF from underside and clean up mating faces.
Addition by TheBoy: Clean the magnet which sits in the large sump. The amount of metal stuck to this gives a reasonable indication as to the state of the box.