BMW X5 E70 automatic transmission fluid change
Does an X5 E70 automatic transmission fluid change need flushing?
ZF's official service is replacing the oil pan and the fluid, and no flushing is needed if the service interval has been followed. In a transmission driven a very long time the fluid is black and changing only the pan leaves about half of the old fluid, so flushing is then better. The 3.0sd's transmission is a 6HP28.
What is done to the mechatronic unit and oil pan, and with what torques?
The 5 seals between the mechatronic unit and the transmission should be renewed, because they compress and can leak. The tightening torque of the mechatronic unit is 8 Nm and of the oil pan 10 Nm, bolts tightened in a cross pattern. The mounting bolts are TX40; TX27 bolts hold the mechatronic unit together, so do not open them.
How is the new fluid filled?
The return hose does not need to be disconnected. After installing the oil pan, add fluid through the check opening, start the car and add more if needed. The level is checked warm and with the engine running, because the fluid drains away when the engine is switched off. Repeat until the fluid runs out clean.