After much hard use, I had the ATF self-flushed (supply fresh ATF and let the old escape with the engine idling) at 61K mi.

Now it's past 140K mi and due for another timing belt. I'll likely have the self-flush done again at that time, but the AT is still behaving itself perfectly.

Volvo's "leave it the hell alone" (ie, treat it as a sealed system) recommendation is not as far-fetched as it sounds to some people. As I 'always' say, the Dexron II ATF is the most over-engineered fluid in your car; there is no way to realize the same levels of benefit by going to synthetic ATF as there is in going to synthetic engine oil (which leads a much tougher life).

If, however, you do a lot of gridlocked stop-and-go 1st-gear heavily-loaded 'driving' in heat-soaked conditions, it might be of some benefit, though it still might be more cost-effective in dealing with extreme use to just change Dexron a bit more frequently (because I've yet to meet anyone who worries about this stuff that has such supreme confidence in synthetic ATF that, unlike Dexron, they'll just put it in and leave it in forever -- and that stuff is expensive...).

- Dave; '95 854T, 143K mi; K+N, DurAlt, Mobil1, Bosch Platinums