[Tannaton]

For some reason on the XC90 Volvo only offered an additional ATF cooler for the 2.5T (T5) models with the AW55 5-speed box (the same box is fitted to the 163 BHP D5).

If I was towing heavy stuff consistently up and down hills I would probably fit one - but don't forget the later cars did have one already in the sense that there was a heat exchanger with the engine coolant in the radiator.

It's hills at sub 50 mph that kills the oil as the torque converter wont be locked. This is when it is very good practice to use the Manual mode of geartronic as you get TC lock up in 3rd, 4th and 5th (on 5 speed models anyway).