Installed PWR heat exchanger and gave the auto a service at the same time... The oil after 115k was discoloured a a fair bit, but didn't smell burnt at all so that's a good sign I guess And what a great kit the PWR one is, everything you need and great instructions, hardest part was pushing the hose onto the barbs And the ZF is so smooth with some new oil in it :-) Also a note to anyone that wants to service their own ZF What ever size tray or bucket you grab to catch the oil, go ahead and double it because the oil goes everywhere haha