I think checking everything else for a cure is just wishful thinking unfortunately.

My friend who owns a 2002 530d with the same gm box suffered the same simptoms as you and then it just refused to go anywhere.

Diagnosis at a gearbox specialist was worn friction plates at a cost of £1600 to recondition the whole thing. They also advised not to touch the fluid ! Another interesting thing was that he said they get at least two bmw's with the gm box every month !

You would have thought that these american boxes would be bullet proof what with all their experience with high torque v8s, but it seems like bmw chose too small and weak a box to handle the diesel's torque.

Topic of interest:

forum.bmw5.co.uk • View topic - 525d/530d autobox warning