2006 auto gearbox questions

[YorkshireDave]

Time to test the collective knowledge - or not

Just about to hit 180K and its fair to say the gearbox has good, not so good and awful days. I'm looking to understand what may be happening and what I can do (get done) to resolve where possible.

On a good day changes are smooth and happen at 2k (revs) unless being pushed.
On a not so good day, driven gently it's reluctant to change up and changes are occasionally distinctly notchy.
On an awful day, when pressing hard (e.g. going up steep hairpins etc) occasionally it will go to change, rev like hell and then suddenly drop into gear with an almighty wallop. When it's happened it's sounded like the gearbox was going to tear itself apart but now I'm far more aware and don't let the revs build up. However when under pressure like that it almost seems to lose drive.

I'm certain the gearbox oil has never been changed, so wonder if that might alleviate things? Or?

Any clues peeps? Any sensible words of advice?

BTW the beast has already cost me 27 king's ransoms but is only worth just half of one

[S60D5-185]

Without a doubt, change the gearbox oil.

A series of sump dumps ( about 3.5 ltrs )with a hundred miles or so between each will eventually get the fluid changed gently until it is nicely pink.

You can also change it in one go with the gibbons method ( do a search ) but personally with your mileage I would just keep with sump dumps.

You need JWS 3309 spec oil and ONLY that no other spec.

Best bet is to buy 20 ltrs from the likes of Smith and Allen in Darlington who are reliable and well regarded.

Make sure that you follow the correct procedure if changing it so that you get the level correct when done.

[Familyman 90]

As above, gearbox oil is worth a shot and may help. Its about the only thing the home spanner jockey can do with these.

Its worth getting a price from a dealer or a marque specialist (definitely not a mere independent) for a fluid change, as they use a machine to pump it out and they'll update the software. The software itself can be transformational. It was a little under £300 at the dealer for mine 2 years ago, although mine was a pre emptive precautionary change.

After that valve bodies are the next culprit, but you're into the realms of auto box specialists. Definitely not a job for the garage round the corner who look after your neighbours corsa. Even a dealer will farm it out to an approved specialist.

[Simmy]

dirty fluid can kill these gearboxes wearing valve body out do some sump dumps as suggested if you get good results with this. do a sump dump at every oil change to prolong the life of the box reset fluid counter when you get it clean

[S60D5-185]

Originally Posted by Simmy

dirty fluid can kill these gearboxes wearing valve body out do some sump dumps as suggested if you get good results with this. do a sump dump at every oil change to prolong the life of the box reset fluid counter when you get it clean

Exactly what I do.

If I already have the undertray off to drop the engine oil it's so easy to just dump the gearbox oil as well and then do a refill / level check and reset counters.

As the phrase goes, fresh oil is often the best set of spanners you can get.

[Simmy]

my auto box has 238k on it but i drive it with respect and keep on top of fluid changes

[YorkshireDave]

Okay. Thank you chaps. Oil changes first then.

So has anyone any idea why it's misbehaving when under heavy load as it is?

[XC90Mk1]

Originally Posted by YorkshireDave

Okay. Thank you chaps. Oil changes first then.

So has anyone any idea why it's misbehaving when under heavy load as it is?

The box relies on fluid viscosity to control selection. If you are lucky a fluid change will resolve it (there is probably a 50/50 chance - fluid degradation would cause those symptoms).

If it’s not the fluid then it is likly to be the valve block, I wouldn’t know how you change that etc to be fair.

I agree totally with the above comments regarding changing oil at each engine change.

[Simmy]

have you checked the condition of the fluid ? under or over filled will cause problems have you checked the level?

[Tannaton]

I would agree 100% that the first step is a fluid change - but I would also say do that via a series of sump-dumps, dropping circa 3 litres and replacing, with a few miles between (50 min). That way you will be diluting the dirty fluid more and hopefully removing more sediment.

Once you have done that, after circa 1000 miles if the fluid has gone black again I would repeat.

If you have VIDA, each time you do a sump dump - clear the gearbox adaptation memory.

FYI I have an XC60 D5 with nearly 150k on, it had a gearbox software update at 100k to cure banging from P to N/D/R which worked but since then about every 6 months it gets very slightly harsh on downshift or upshift into 2nd - if I reset the adaptations this goes away again. It is slight though and I think many drivers wouldn't notice it.