My 940 estate seems to be giving out knocking sounds from the rear under hard acceleration in 5th from 60-75 or so. It sounds like small bumps on the road a few times a second or so, but is definately linked to acceleration and doesn't occur at different revs on the same piece of smooth road.
It does get a bit of a hammering, have I worn out the universal joint, or the support bearing or something?
1995 940 SE 2.3 Turbo estate, 115,000 miles-- Tony Stanley ++Always Learning++
I would first check clearance around the exhaust pipe and make sure all rubber devices are in place.
The exhaust doesn't go anywhere near the drive shaft at the rear, and is well secured. I'm faily sure the noise is comming from the rear, and I think I would know the difference, its just not that sort of noise.
Its getting worse now, or I am looking for it more. Full tilt in 1st now feels very rough.
-- Tony Stanley ++Always Learning++
I did not mean that the exahaust hits the drive train, possibly the underbody of the car.
If you do have a mechanical problem, there are several candidates:
The Hardy disk (rubber thing) at transmission rear end. I have read that these get worn and cause vibrations, without loooking noticeably bad. They are a bit expensive to replace "just-in-case". I never had one fail myself.
The support bearing, or rather its rubber housing. Same thing. Never happened to me. One bearing went bad, but it created noise, a whining sound like circular saw or so.
U joints. When they get worn (or jammed) they cause vibration and make noise, although in my limited experience at all loads. I had one jam, causing vibrations at highway speed. Sound and vibration was pretty much independent on load. Same when coasting or accelerating.
a bad u joint would be my guess...does the spped of the knocking change w/the speed of the car?
Also check your engine and gearbox mounts.
Cheers, Peter.
: > If you do have a mechanical problem, there are several candidates: : >
: > The Hardy disk (rubber thing) at transmission rear end. I have read that : > these get worn and cause vibrations, without loooking noticeably bad. : > They are a bit expensive to replace "just-in-case". I never had one fail : > myself. : >
: > The support bearing, or rather its rubber housing. Same thing. Never : > happened to me. One bearing went bad, but it created noise, a whining : > sound like circular saw or so. : >
: > U joints. When they get worn (or jammed) they cause vibration and make : > noise, although in my limited experience at all loads. I had one jam, : > causing vibrations at highway speed. Sound and vibration was pretty much : > independent on load. Same when coasting or accelerating.
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