DIY ZF 6HP19Z Transmission Drain & Refill
Procedure: This method should also apply to most E60 models. I would expect fluid levels to be different due to differences in the torque converters for the higher HP/torque models.
History: ZF developed a 6 speed code named 6HP19, with 6HP19Z designation for the BMW unit. These units came with BMW "lifetime fill" ATF, which is listed in the BMW Operating Fluids Manual, Groupe 24, as Shell M-1375.4, only available at the dealer. I priced this fluid at the dealer at $16 for ? liter. I instead opted to do some research and found two alternatives for this fluid, Pentosin ATF1 and ZF-Lifeguardfluid6 AT fluid. ZF and Pentosin fluid can be found at dealers. People have found other alternatives with labels stating that their ATF is compatible with Shell but I decided to play it safe. Unfortunately, ZF decided to make the pan and filter as an integrated unit made out of plastic. So, you must change the pan and filter as 1 piece.
Note: You will not be able to completely drain all the fluid out, instead some fluid will remain in the torque converter. Factory fluid capacity is 9 liters. One drain gets 5.5 liters out, so you get you close to 60% new fluid on one drain and refill. Subsequent drain and fill will get you close to 90%.
Parts Required: ZF transmission filter kit, Transmission fluid of your choice.
Tools Required: Sockets: 8mm, 10mm, 16mm, Torx T-40, 8mm L-shaped hex, Torx E10, 10mm hex head, 13mm ratcheting wrench, 3/8 Ratchet, Phillips screw driver, floor jack, 4 jack stands, ramps, oil catch can, fluid pump(available at any auto store).
WARNING: ZF has strict temperature requirements for fill. As per ZF, when adding new fluid while the engine is running, the temperature of fluid should be at 40 deg C. Oil temperature MUST NOT exceed 50 deg C. If the temperature gets past 50 deg C, you must allow transmission fluid to cool down before you start the fill procedure again.
1. Put the car up on stands on all four corners. I found the best way to do this was by 1st driving the car on ramps, then lifting the rear of the car by the differential. Always place a piece of wood between the jack and differential to protect it from damage. Once the car is up in the back, place jacks on the jack mounting points on the sides of rocker panels.