You have the 2.5L which is mated to a Aisin Warner AW50-50/51. The AW50-50/51 cannot be serviced without disassembly. The picture shows the location of the ATF filter. The bolt next to the large gear is what holds the filter in place.

The transmission is not a Volvo transmission.
Nothing in the service schedule about changing the filter.
They are good transmissions, with laser cut gears and advances in fluid technology, I can see a filter lasting the lifespan of a transmission. Make sure you use a JWS 3309 transmission fluid.

Only the 6 cylinder 2.9 and T6 models are lucky enough to have the GM transmission which does have a replaceable filter. The AW transmission is a Japanese transmission that I understand has no filter, only a internal screen not serviceable. Oh you must never add fluid other than the exact specific f...

No it is not the GM transmission. Aisin Warner is the name of the manufacture of the transmission mated to the 2.5L. I cannot locate enough information to determine if the Valvoline Import full synthetic is OK. The Volvo part number for the ATF is 1161540. Correct Aisin-Warner ATF Valvoline MaxLife ...

Here are pictures of the dipstick location for GM and I marked where the AW dipstick would be. You can't mix the two locations up. June

The cap could be bad. The cap is to regulate pressure no higher than the set pressure indicated on the cap. Replace the cap and see what that does. For Volvo there is a green cap our S80 came from the factory with, and a black cap that holds 1/2the pressure that is the correct cap for a 1990 240. Th...