BMW F30/F31 xDrive transfer case faults
F31 xDrive: drive is lost or the car does not move even though a gear is engaged. What is the fault?
A possible cause is the flange at the transfer case's rear output, whose splines have worn smooth. Then power is not transmitted to the front either, even though the gearbox itself is fine. A new flange fixes the fault. Let a workshop diagnose it.
Why does an xDrive car jerk when accelerating or in a corner?
A common cause is a transfer case fault. In the higher rev range the jerking often goes away with a transfer case oil change, while jerking in the lower range points to a bearing fault. Tyres of different sizes or different makes can also cause jerking.
How do tyres affect the xDrive transfer case?
The rolling circumference of the front and rear axle tyres must be almost the same, otherwise the transfer case is strained. The same tyre size does not guarantee the same circumference, because make and model affect it. Replace the tyres as identical sets on both axles.
What oil is used in the F30 xDrive differentials?
According to BMW's part numbers, the front gets Hypoid G2 and the rear gets Hypoid G1. The LS marking means the limited-slip additive; for a rear differential without a lock, an oil without it is suitable.