A new clunk!

[fudge_sta]

Hey guys would like your knowledge on a recent clunk that has developed from my car,
Car is a late M20 325i cab, and symptoms are as follows,

When moving off from stationary (when raising the clutch at the point where everything start to make the car go forward) a clunk/thud seems to occur in first and second gear only. This is only as i set off and it all seems normal till i change to second and release the clutch. Can be avoided if im very gentle on setting off from stationary.

Noise is also present when handbrake applied and bringing clutch up to biting point. (Noise is only when biting point archived and lasts for less then a second)

From listening to it inside the car i think it to be coming from the rear possibly differential or prop shaft area. (Although i am no expert)

I recently have had the rubber guibo and CSB replaced and i am aware that the release bearing on the clutch needs replacing as occasionally rattles and differential has developed a leak although i didn't think this would be a cause of it.

Any suggestions would be great, Thanks

[steve_k]

I could be wrong but it could be the rear beam bushes are on their way out,

Had a similar problem on mine till I changed the rear bushes.

Could be wrong though.

[jimmyspeed]

rear top mounts also clunk, - easy fix and you can put uprated oem e46 ones in too

[Speedtouch]

Best to jack the rear of the car up, place it on axle stands and get underneath and rotate the propshaft back and forth with the car in neutral. Look at the differential, paying close attention to the mounting bolts on the diff input flange, and try to feel where the clonk is coming from.

Could be loose propshaft bolts, or worn differential.

My first E30 320i did a similar thing, and it turned out to be a gearbox mount on the back or top of the gearbox - a b*tch to replace, as you had to remove the exhaust, undershield, propshaft, etc, etc.

[fudge_sta]

With regards to rear top mounts they were changed around 2 years ago when i put new bilsteins on the rear with lemforder top mounts so i don't think they would be the cause, although i was told by my previous mechanic that the rear axle carrier bushes were in need of changing. Engine and gearbox mounts are fairly recent also IIRC.

[daimlerman]

Are the four bolts that hold the diff to the rear axle carrier tight?