Yes, both of these. Volvo originally designed the transmission oil cooler as modular, so its capacity could be increased. I don;t know if it still it, but if it isn't you need a bigger oil cooler. You may also need additional engine cooling , such as an extra fan if it does not already have two. And change the transmission fluid every 3 years. If there is a dipstick (probably not) the simple check is that the fluid should be pink at best and red at worst. If it's black, it's burned and needs replacing. You also need to remember to idle the turbo/turbos for a couple of minutes whenever you stop after towing to keep oil flowing through the bearings while the turbo cools from almost read hot.