[driverman]

Originally Posted by Healey3000

Hi,

Sorry to hear of your problem. Let's step through the drivetrain from front to back to see if we have thought of all possible culprits:

Dual-mass flywheel - a failure there would not result in these symptoms.

Clutch disc - if this has completely disintegrated, you could have no engagement but the clutch might feel normal. The input shaft to the gearbox may not spin, depending on the type of failure. Grinding noises may result.

Gearbox - As others have mentioned, the shifter may not be actually moving the shift forks. However, I think it's doubtful that grinding noises would result and for that reason, I don't think the problem lies here.

Driveshaft - If these cars use the traditional BMW guibo to couple the output shaft of the gearbox to the driveshaft, then it is possible that yours has failed (there may also be one at the differential end). Grinding noises are possible if it has shattered such that there is no coupling but it's able to spin freely. Likely suspect.

Differential - A stripped pinion gear would do the same thing with respect to noises and lack of traction. However, it's hard to imagine such a failure as other things are likely to go first.

There is one thing you mention in your post that leads me to believe that the problem is downstream of the gearbox and that is that the "noise is louder in higher gears". This suggests that the rotating object that is causing the noise is changing RPM based on your gear selection, therefore, downstream of the gearbox.

Simple things go wrong more commonly so my first inclination would be to check to see if the driveshaft is rotating at all. If it is, the guibos would be the next thing to check. Basically, divide the problem areas into pre-gearbox and post-gearbox. At least that reduces the number of things to consider.

Good luck and please let us know what you find.

Regards

Great post!