Hi, just looking for help in determining where a thumping sound is originating from.
Background:
My sons each have an e30 coupe that we have completely redone and swapped M30B35s into. Both have been running great for a couple of years now, however 2 weeks ago the 1987 coupe started to make a thumping sound that seems to transfer into the cab area thru the centre console and we are struggling to find the cause/cure.
Symptoms:
1) The thumping appears to be transferring into the cab area thru the drive shaft centre bearing bracket.
2) It occurs around 2,000 to 2,600 rpm when the motor is under load. The sound seems to disappear above and below these rpms.
3) The thumping increases and decreases inline, more or less, with wheel speed, not engine speed.
Work done to date:
1) Inspected all wheel bearings. They are fine.
2) Thought it might be the drive shaft u-joints or the centre bearing. Removed drive shaft. U-joints are fine and the centre bearing and rubber are fine. Giubo is just like new. Everything was tight and centre bearing was still preloaded. Just to be sure, we swapped the driveshaft out of our 1986 coupe into the 1987 and the sound was still there.
3) Thought it could be the differential pinion bearing. So removed the 2.93 differential and installed our extra 3.73 Differential. And the sound is still there.
4) Checked clearance between engine/driveline and the car's body and its all good.
5) Checked the Condor engine mounts and tranny mounts and the are all good.
Just wondering if anyone has experienced anything similar??
I appreciate any input or advice you can offer.
Thanks
Background:
My sons each have an e30 coupe that we have completely redone and swapped M30B35s into. Both have been running great for a couple of years now, however 2 weeks ago the 1987 coupe started to make a thumping sound that seems to transfer into the cab area thru the centre console and we are struggling to find the cause/cure.
Symptoms:
1) The thumping appears to be transferring into the cab area thru the drive shaft centre bearing bracket.
2) It occurs around 2,000 to 2,600 rpm when the motor is under load. The sound seems to disappear above and below these rpms.
3) The thumping increases and decreases inline, more or less, with wheel speed, not engine speed.
Work done to date:
1) Inspected all wheel bearings. They are fine.
2) Thought it might be the drive shaft u-joints or the centre bearing. Removed drive shaft. U-joints are fine and the centre bearing and rubber are fine. Giubo is just like new. Everything was tight and centre bearing was still preloaded. Just to be sure, we swapped the driveshaft out of our 1986 coupe into the 1987 and the sound was still there.
3) Thought it could be the differential pinion bearing. So removed the 2.93 differential and installed our extra 3.73 Differential. And the sound is still there.
4) Checked clearance between engine/driveline and the car's body and its all good.
5) Checked the Condor engine mounts and tranny mounts and the are all good.
Just wondering if anyone has experienced anything similar??
I appreciate any input or advice you can offer.
Thanks
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