All automatic and most manual gearbox versions of the E53 models possess a lifetime lubricant, which means that they never will require oil changes during their useful lives. During the repair of transmission or transmission oil cooler, lifetime lube oil should be used and only that which has been approved should be used. One of the weaknesses I found in the automatic transmission is that the transmission does not have a dipstick to check the condition, and one has to follow a particular procedure of measuring and ensuring the ATF is at a relevant temperature before checking the level. MTF-LT-1 is an exclusive lifetime fluid used to fill manual transmissions, and guidelines for inspecting and replenishing this liquid are also present.