There is a dip stick...it's just that it's location is very hidden. Volvo doesn't want us to touch it. If you look under your larger intercooler pipes from the front of your car, just to the right of your engine, you'll find it way down deep...it has a yellow handle, and a clasp on the under side you have to push it to get your dipstick out. Btw, Volvo transmissions don't have a filter. Some people add "magnetically charged" in-line filters to their tranny lines...not a bad idea, really.
You may want to check this out:
www.ipdusa.com/Products...D=629
Altough it's a "for sale" section of IPD, the pdf file in the middle of the page shows you how to do the flush (if you choose to let your mechanic do this), and the instructions are good....same instructions for most all FWD/AWD Volvo's.