Hi guys, first time posting here but I've been reading the forums for a while now as I navigate through the joys of R56 maintenance and repair ;-) Hoping someone can shed some light on an odd transmission (manual) issue I'm having before I throw a bunch of money at a goose chase. Symptoms are as follows:
When cruising along on the highway, and just maintaining speed, the car will act as though it has slipped out of gear / into neutral. The gearbox is still in the correct gear, and the shifter has not moved. If I take my foot off the gas, once the revs drop to around 3000 the clutch seems to automatically re-engage and I can carry on. It has happened in 3rd 4th 5th and 6th. I've tried depressing and releasing the clutch pedal and this does nothing to re-engage the clutch. It will only re-engage either once the revs have dropped or if I put it in a much lower gear. It has happened occasionally while driving in the city but seems to happen most often when just cruising on the highway. There does not appear to be any clutch slip under load, even WOT/full boost.
The other thing I have noticed is that there is a low grinding sound coming from under the car when the clutch is engaged and I'm driving. It happens both under throttle and when I'm off throttle. I thought it was a maybe a wheel bearing or a grinding rotor but I noticed that the sound stops when I push in the clutch. I should also mention that when the car slips out of gear/ into neutral, while the engine revs are spooling down there is a different spinning/grinding sound... sounds more loose or something, hard to describe but it's not the same as the other grinding sound.

Any ideas? I had a guy at a transmission shop take it for a spin and he says he has no idea and has never seen something like it in the 35 years he's been working on cars.

Any help/advice is much appreciated! Thanks!

-Mertz

 

How many miles on the car?

Sounds to me like you need a new clutch.

 

did check the MT fluid?

 

I'm with skibum, clutch is slipping.