2004 manual 2.5i X3 presumed play in drivetrain

[X3wilts]

I'm trying to find why my car clunks when the clutch is let up. It's only a light clunk but audible. It also has a tendency to get stuck jerking when the accelerator is let off like a sort of resonance like a slowly decaying bounce. I think it's either my flex joint, center bearing or my u joint. But can't be sure is there a way to tell the difference? Or maybe all of them? Tia

[X5Sport]

What tyres are fitted, and what wheel size (inc width)? X3s are very sensitive to tyre choice and getting it wrong can and has damaged the transfer box in particular. Tyre wear differences axle to axle or even tyre to tyre can cause transmission wind-up and the stress can give rise to other issues.

[X3wilts]

Thanks for the response,

255 45r 18 on the back
235 50r 18 on the front

[X5Sport]

All X cars need to have very even tread wear between axles, no more than a couple of mm difference front to rear or on the same axle.

E83 are known to be sensitive to having non ‘*’ marked (it’s visible on the sidewalls) tyres fitted, with some tyres leading to damaged transfer boxes or diffs. It may not be your cause, but worth checking. The mark means the tyres are specially made for BMW cars. Merc, Audi, Porsche and others also have their own version (and marking schemes).

[kkx5]

....As always....remove fuse no26...test drive it.

[X3wilts]

I've checked the tyres all round and they are all evenly worn they also have the * marking on them. Good to know for when I get new tyres as I wasnt aware about how sensitive the system is to them. I've also driven it with the transfer box disabled and seems to make no difference still auidable clunck when changing gears and pulling away. It's going in for its mot so I've just asked the garage to look into it when the have up on the ramp and just check for play in the propshaft. When I find out I'll post an update. Thanks for all your help

[X3wilts]

Okay late update but it was both the flex disc and the centre bearing that had gone. The clunck came from the whipping from old flex disc.