Finally got the time to attack the trans oil service, and I've gone through all the relevant posts for the fluid change. What took me a while was figuring out which was the drain plug! I'd seen the drawings from the service publications, but under the car it didn't leap out at me, and I was looking for a horizontally-oriented plug. Found it, and for anyone else who needs a little direction, it's circled in the first photo below.
Absent a helper, I elected to do the simple drain-and-refill method. The job is conceptually simple, but I ran into some problems which I was fortunate enough to conquer. First, removing the fill plug was ridiculously difficult! It took a 1/2" drive breaker bar to crack it - which tells me the trans had never been serviced before today. (And as a reminder, any time you plan to drain a trans or a diff, ALWAYS open the FILL port first to make sure you can refill after you drain! Long story behind that advice.) Next, draining almost didn't happen! The cheesy little level-port screw (with the Torx 40 head) seems to be made of aluminum or pot metal, and it was nearly as tight as fill plug. As I applied torque, the head started to strip, and that could have gotten ugly. I used a hammer on the drive tool both to bottom it firmly in the bolt head, and also to help break the "stiction." That worked, and blessedly the bolt came out. The final "problem" wasn't much of one, but at least two sources had claimed that the aluminum crush washer on the main trans plug was identical to that used on the engine oil pan plug - nope. The trans plug is a larger diameter. I'll chase that down and find a replacement bolt for the level plug as well.
The rest of the task was as uneventful as it should have been. About 3-1/4 quarts drained out, and I simply refilled the trans with the same volume of fresh Mobil 3309. The old fluid was pretty dark (see pics) and poured about like water, but I was encouraged that it neither smelled nor tasted burnt. The drained ATF (at 117K) was not opaque, but it surely convinced me that "no service necessary" for the Volvo automatics is somebody's pipe dream. I'll repeat the procedure at the next few oil changes .
