Great advice, and I'd also add that ANY transmission problems should immediately be followed by a fluid flush unless you're positive you have perfect fluid. Many people NEVER change the fluid (why would they really, it's not in the service schedule) and these transmissions NEED clean fluid. DEX-III is pretty cheap and you can do a flush with minimal tools and time - it should be automatic.
Of course, waiting for problems to surface is probably not the best approach either. Pre-emptive maintenance is always better. A 50k mile interval is probably not excessive for these cars. If you're towing I'd put it down to 30k miles.
Synthetic fluid is better for leaving in the transmission, but cheap fluid is good for a quick cleaning flush.
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1998 V70 AWD->FWD->AWD Turbo 220k+
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