I'm currently sitting at 156k and would like to do a fluid service. From reading up, this is the only year this car had this trans? What is the specific recommended procedure for doing this?

It acts mostly fine, when it's very hot the shifts take a split second longer than cold. I've had the updated software pushed over a year ago, once in a blue moon at low speed the downshift can be harsh. I'll take any recommendations into consideration. I'm pretty handy with this car so far, so most work I can do myself (if recommended).

This is the 5-speed auto.

 

IPD has kit to help change fluid. Use Mobil 3309 or equiv.

 

Are you talking about this? Volvo Automatic Transmission Flush Hose Kit IPD 107945 T7072

Should I really do a full flush? I've read places that can "shock" the trans, though I see the reasoning behind getting all dirty fluid removed, as well.

I also haven't read much on reliability of this particular transmission, what's the general consensus on it?

 

It's the AW-55, same as the S60 got for early to mid 2000's. Not a perfect trans, but not horrible. Mine had the fluid changed once at 90K when I bought it at 141K. I flushed it with the IPD kit, then put it on a drain/fill routine for the next 4 oil changes (every 5K) as the fresh additives worked at the build up. It now has 190K on it with no signs of issues. The fluid looks pretty good still and I have been using Valvoline MaxLife since it is compatible for this particular trans and full synthetic. I'll probably run it until 200K before I start the drain/fill routine for the next four oil changes. That works for me because I drive 5K in about 8 weeks.

You may also want to research the B4 servo update. It may help with your shift issues.

 

Thanks very much for the info, I really do appreciate it.

Found the B4 Servo: Automatic Transmission B4 Servo Cover Update AW55-50/51 GENUINE VOLVO 107960 30651771 30751262 KIT-30751262

I'll also order that flush kit and get the Valvoline MaxLife you are using.