Hi all
After years of enjoying and caring for a 745T, I had to pass the buck to a more mechanically enclined owner (who has vowed to bring her to 300k and shows he will)… now I am discovering the XC70 (and, while enjoying modern aspects, believe it or not... regret certain features of the 740: turning circle, overall visibility, “sharper” brakes…).

I have an issue with the transmission I hope someone can relate to and help me remedy.
This well maintained 2003 car already has 186k highway miles, the transmission was never rebuilt nor flushed according to the previous sole owner. It shifts smoothly for about ½ hr of driving, after which the transition (up or down) from 1st to 2nd gear (as far as I can tell) can be very bumpy!

Any idea about what is causing this and how to cure? I am thinking of two possibilities: 1/ not enough ATF and as it warms up, becomes more fluid and there is not enough in the system for smooth shifting. Or rather… 2/ sludge which would progressively mix as the car gets driven and make these transitions so rough…
My mechanic (who is not a Volvo specialist) says these transmissions are sealed though, and is not keen to mess with it… but a quick search on the Board shows people do indeed “service them” (flush).
Would a “simple” topping off work? if the yellow “dipstick” is just a plug then, how to measure what’s needed?

Or should I talk my mechanic into doing a complete flush (he has a flush machine), if so, what would be the right amount of fresh ATF and best ATF brand/grade to use?

I was hoping to use this car for a long trip and would greatly appreciate any thoughts and suggestions from XC70 owners who have experienced the very same situation…