If you check the original Volvo owner service specifications, Volvo called for a trans fluid change at 22.5k mile intervals for the AW60 transmission. When the AW70 came along they stopped calling for the fluid change, rather saying to CHECK the transmission fluid every 20K miles. The published owner service manual only went up to 100k miles, so most assumed that to mean change the fluid at 100k mile intervals, which is what many of us try to do. When the AW71 came along, Volvo again changed the service interval to replace the fluid at 40K mile intervals. Believing these are fundamentally a similar internal design, I try to stick to a 60K mile interval (100k km) if done regularly, or else as needed if trans shifting behaviour becomes noticeably delayed. Trans shifting behaviour is also due to worn internal ball valve packs, so keeping them as clean as you can obviously helps, as does switching to synthetic.
Volvo used to specify trans filter element inspection and replacement at every change interval for the AW60, but stopped recommending that many years ago. Anytime I used to pull the filter it was always quite clean. The trans filter for those who may not know is a shallow fluid settling pan, not a particulate screen. It doesn't come with a magnet, but some later added one, as well as at the drain plug. It is easily cleaned, but for dealer service it was probably cheaper to simply replace it. It's a messy pain to drop the trans pan for access and I'm guessing Volvo thought it better to have the fluid changed more regularly rather than delaying service because it was a more expensive proposition labour-wise, hence going back to a 40K mile fluid-only change interval. Many of us happily drive our AW7x automatic transmissions for 100s of thousands of miles doing only regular flushing at the transmission cooler lines (as should be described in the FAQ) rather than simply draining the pan and refilling as is generally called for. Being able to keep flushing while running it through the gears has definite advantages and you keep flushing until the fluid runs clear.
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Dave -still with 940's, prev 740/240/140/120 You'd think I'd have learned by now
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