E90 - Thought clutch had gone, but driveshaft still spins...

[TroubledSoul]

Just checking I'm not missing anything here for my own sanity really. I pulled out of a junction on Saturday and the car suddenly lost all drive. No bangs, or weird sounds. Just wouldn't engage when I released the clutch. I can actually lift my foot completely off it and it doesn't stall. I thought the clutch had gone.

Then I looked under the car this morning, with it in gear. The driveshaft spins. So it can't be the clutch or gearbox, unless I'm being thick? That leaves the diff. The weird thing though, is I thought I'd felt the clutch slip a couple of times in the last week, then thought no, I've imagined it. But if it's the diff, is it possible for the diff itself to have slipped?

I should probably add, I've owned it a week and was very happy with this "bargain" manual 330i

[Mercdriver]

Limited slip diff? Broken half shaft?

[TwinKam]

By 'driveshaft', do you mean 'prop shaft?
Obviously chock the front wheels for both these tests as you need the handbrake off.
If you can safely support the car with the rear wheels free, do the same check and see if either or both wheels turn with the engine running and in gear.
Or jack each rear wheel separately and see if you can turn each wheel by hand with the engine OFF but in a gear.

[stevieturbo]

And did you pull out of the junction like a normal person, or at 5000rpm dumping the clutch ?

And as above, are you referring to the propshaft, or the pair of driveshaft axles ?

And is it any different in any gear ?

[TroubledSoul]

stevieturbo said:

And did you pull out of the junction like a normal person, or at 5000rpm dumping the clutch ?

And as above, are you referring to the propshaft, or the pair of driveshaft axles ?

And is it any different in any gear ?

Of course I pulled out like a normal person, I'm not a 20 year old dhead leaving a car show

So it turned out to be the halfshaft on one side had come completely off the diff flange. The bolts had literally just backed out. Further research suggests they're stretch bolts and should only be used once, so I can only speculate that someone has had it apart at some point and re-used them.

£27 later and a trip to BMW and I've put a new set in and torqued them up. All sorted Bit of a relief!

And yes, I meant the propshaft.

[camel_landy]

TroubledSoul said:

So it turned out to be the halfshaft on one side had come completely off the diff flange. The bolts had literally just backed out. Further research suggests they're stretch bolts and should only be used once, so I can only speculate that someone has had it apart at some point and re-used them.

Yeah, that'd do it... Power... Path of least resistance... Yada...

Glad it was a simple fix but it does make you wonder why they undid it all in the first place. Hopefully there's nothing lurking.

M

[TwinKam]

Odd, I woulda thought that would be making an unmissable racket looooong before the bolts came out.
I've found noisy ones in the past that only needed1/8 turn on each bolt to fully tighten.

[E-bmw]

^^^^ Wot e' said.

It would have been noisy to at least some extent for some time.

[TroubledSoul]

Genuinely didn't hear anything, although I wouldn't have known it didn't sound normal I suppose since it was probably starting before I got the car.

There's some mention on the old MOTs of the rear subframe being weakened or corroded and it looks to have been professionally welded having now been properly under the car, so the diff etc. were probably taken off to do that. I'll have to check the other side periodically.