Transmission Oil 760 Turbo 1986 Auto
 

Tips on changing the gearbox oil?

Any help for a newbie and what oil should be being used? Garage said this doesn't need to be changed.

Are they right?

63000 miles.

I just wanted to do it for peace of mind really...

Garages tend to advise against replacing transmission fluid in an older car because doing so can cause problems for which they don’t want to be held responsible. I think Volvo changed their advice to leave the fluid for the life of the transmission unless towing or driving in a harsh climate. What they didn’t say is that the transmission probably wouldn’t live as long without regular fluid changes.

Your car probably has an AW71 transmission as it’s a turbo model. Does it have an overdrive switch? This is a tougher transmission than the ZF box used on non-turbo cars of the vintage. Either would probably benefit from a fluid change if the fluid is dark and smells burnt.

The most popular method is gradually to drain and mix in new fluid over a longish period until you’ve done this often enough to have nice clean fluid. This is less of a shock to the transmission and helps gradually to lift dirt out of crevices.

On my 940 I just went straight in and changed the fluid in one session using the gibbons (or cooler line) method with no ill effects. I didn’t drop the pan or change the internal filter as others have said it’s rare to see one that dirty but if you want to do a proper job that might be worth considering.

Okay. Are there any guides on:

1) checking level
2) draining/ changing filter
3) topping up and which oil to use.

Not sure what type my car is. It's a 760 Turbo Intercooler 1986. B230ET Engine.

I'll go for the last one first :

https://www.ebay.co.uk/itm/Carlube-A...e/233257297843

Next, like Forrest says, garages tend to run away from changing gearbox oil, especially autos as they don't really understand them. Sadly because of that, they often give incorrect advice as they have this time!

If using the "flushing method" as described by Forrest, it should be done every 24k miles or 2 years.
However, i favour the "part-change" or "sump-dump" method. Two ways of doing it, one is jack the car up so it's level and remove the drain plug in the transmission sump pan and let the contents flow out into a suitable container, refit the drain plug and refill the box via the dipstick with fesh oil - usually 2.5-3.5L

What is easier is to get the car facing downhill and use a fluid extractor pump.

https://www.ebay.co.uk/itm/Car-12V-6...e/352754565259

Feed the suction pipe all the way down the dipstick tube to the bottom, arrange the discharge (larger bore) into an empty 5L container, connect the clips to the battery then switch on and go and have a cup of tea, coffee or whatever for 20 minutes.
Come back and see how it's doing, should be nearly finished pumping. You'll know when it has as it will start making squelching noises and the fluid will come in fits and starts.

Switch off and discoinnect the clips, remove the suction tube from the dipstick and put the pump, 5L container out of harms way then top up the fluid on level ground to the "COLD" mark on the dipstick with the engine idling in N or P.
Take it for a drive to warm up the fluid and recheck again on level ground, topping up as necessary.

All methods should have the fluid warmed up first by a drive of 5-7 miles, be careful as it will be hot. If using the part-change method, repeat after a month to total 3 or 4 changes, depending how clean the third lot comes out.

Repeat one part-change a year after to keep the fluid clean and fresh.

The big danger with doing the flushing method, especially on an old box, is the "seal swell" in the ATF will have worn off, allowing the seals to dry and become brittle. THis means when a complete load of new fluid that is much thicker goes in, it's all too easy to blow these seals. Doing the 3 or 4 part changes a few weeks apart gives the seal swell in the new fluid time to revive the seals and clean the inside of the box so more and more dirt will be removed each time until it's no longer dirty inside. This also helps clean the filter too as the deteregent effect of the new fluid causes the debris on it to drop off as it's no longer dirty. This gets removed by the pump when you use the extractor pump method.

Glad you've brought this up as it's reminded me i need to get some ATF-U to do the annual change on both of beasties. I use ATF-U as it's Honda Z-1 comatible so is suitable for my other beast and it's also JWS3309 compatible which means it's good for the Toyota A341E box which is pretty much identical to the AW-71 boxes we have in ours.
I have also used it in a ZF4HP22 in an XJ Cherokee i used to own so even if you have a ZF box in yours, you'll know it's ok for that too.
Can also be used as PAS fluid (again, both of mine are using it) and numerous other uses too.

Think i've covered everything there, feel free to ask if not. :thumbs_up;

Super mate. Nice and easy for a newbie to understand. I'll probably try your pump method. Would you suggest just using the pump via the dipstick until 2 to 3 litres is out. Then replace with 2 to 3 litres fresh. Then leave as you have said for a year or so.

Thanks again. Really helpful.

Is the Carlube stuff good enough?

Empty out as much as you can with the pump, not just 2-3 litres. That will leave a lot of dirt in the bottom of the box to make the fresh fluid dirty so empty as much as possible each time.

As for Carlube ATF-U, i've been using it for many years and yes, it is definitely good enough! Analyse the fluid in either of my gearboxes now and you'll find ATF-U and the same goes for the PAS systems. You'd also find some mixed in with the engine oil on both cars for other reasons, traces of it on various fasteners (50:50 acetone:ATF-U mixed and shaken before each use is an amazing penetrating oil and works out about 1/4 the cost of WD40 and is ten times better minimum) and even some in the fuel tanks.

Thanks again. Lastly, whilst you mention, fools guide to Power steering change? And the option for fluids for this?

These two jobs anre the only two garage didn't recommend...

Again, i use ATF-U in my PAS, found it's better than Dexron II-D which it's compatible with among others.

Get yourself an empty Pot Noodle pot and one of these syringes :

https://www.amazon.co.uk/gp/product/B009LEEOVW/

Use the syringe to empty the PAS reservoir, top it up with new fluid and then start the engine, turn the steering lock to lock a few times until the bubbles stop appearing, topping up again if necessary. Repeat at weekly intervals until the fluid remains clean, usually 3-4 repeats.
Discharge the syringe into the Pot Noodle pot, being white it will show the dirt in it. Decant at your leisure into a larger sealed container for disposal or allow to settle and use it to help prevent rust, paint wooden fences or similar :thumbs_up: