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High ATF temperature can be addressed via replacing it more often (every 10k miles or less). I do not know if too much ATF replacement can cause any harm.
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10k, for ATF, on a fairly modern autobox, seems way overkill, unless you truly do drive in quite harsh conditions - and then you'd have to question your choice of vehicle.

As it stands, I hardly think it makes sense to over-maintain the hell outta your car / autobox, because you wanna drive it out of the envelope, in order to make it perform better.

I honestly think it would make more sense to consider a change of car - either for a more powerful one, or a manual transmission, if the one you've got is not up to your performance expectations, such that you are prepared to over-maintaint it so.

I mean every 10k for a fairly modern autobox is almost at engine oil frequencies. And it ain't cheap. Surely that can't make sense to you?

I know that here in the UK, the residual value of my 98 S70 auto, ain't particularly that much any more - surely the residual value of a 93 850 isn't gonna be much in your neck of the woods? Surely it would make more sense to bite the bullet and trade for a car that performs more to your needs / expectations (either in terms of power, or transmission) - than go all ballistic on maintenance?

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However, AllDAta.com service manual specifically mentions that it should be replaced only if high temperature is recorded or under extensive towing or burnt odor / discoloration of the ATF occurs. I do not know why.
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Because ATF isn't subject to the same degree of contamination as engine oil. And fairly modern autos are manufactured and electronically operated to better tolerances than the autoboxes of yore.

When I said monitor your ATF - I merely meant monitor. Check the level, colour and characteristics every so often, and see whether it shows evidence of thermal degradation - and if necessary, change it as appropriate.

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I may use D3 during short distances (10 or 15 minutes drives and under 3000 engine rpm). I hope that is OK.
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I would consider it like this, D is for normal driving. If driving in hilly terrain, or when the ECU seems to be slightly wrong footing you, drive by *exception* then. But for normal stuff use D - you shouldn't have any concerns, then.

If the demands of your drive truly make 3 more *appropriate* I'm not suggesting you shouldn't use it. I merely suggesting that to use it to make it perform better, for normal driving seems quite flawed.

If it truly is that much of a problem for you, surely a faster and / or a manual car is what you'd be more suited to.

It just seems like you asked the question, looking for a certain answer, and when some answers aren't quite to your suiting, you still seem to want to fight it at all turns.

At the end of the day, it's your car, to do with as you will. If you truly do *honestly* want the question answered, arbitrarily, rather than with a certain polarisation, write to Asin Warner or Volvo, or both. Perhaps if you phrase the question quite detailed, given what has come out of the discussion here, you never know, you may well get a reasonable answer, rather than the normal, corporate fob-off speak.

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Lo Pan's Ghost