[Tannaton]

This topic crops up frequently and there is usually a debate about causing more damage if you replace all the old, dirty fluid with new. No-one on here has ever reporting encountering that.

In my mind it's like declining emergency heart bypass surgery because of the small chance you might have an allergic reaction to the anesthetic...

Everyone who changes the oil reports improved gearbox "manners" afterwards, even if it doesn't fix all the pre-existing problems.

Whilst the TCM adaptation memory should be reset (or even better the full adaptation process completed), it's not a huge problem if that is not done as it will mostly re-adapt over a short (500 miles?) time. Not resetting the TCM after a fluid change will not cause any new errors or messages directly.

Although Volvo do not include trans fluid changes in their service schedule - they do recommend it every 36k for "arduous use" vehicles (taxi, towing, hot climate etc.) I think I would be correct in saying that the experienced Volvo dealer mechanics on here believe that many transmission failures could be avoided by changing the fluid at sensible intervals (say 50-70k for normal domestic use) and would change the fluid in their own cars.

Other manufacturers that use the AW55 and TF80 in their models usually recommend fluid changes, the longest interval of which I think is Jaguar at 150k (this was latterly introduced after about 3 years of them launching the 2.2D X-Type auto which uses the TF80).