Clonking rear end
Clonking rear end
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Discussion

davidn

Original Poster:

1,028 posts

288 months

Thursday 9th January 2003
quotequote all
I am getting a clonking/clanking sound from aroud the diff/rear of the transmission tunnel. I have the car up on stands at the moment and have run the car in gear (at around tick over) 1st, 2nd & 3rd no noise, but 4th & especially 5th there is a pronounced clonking. I had noticed this before when driving but put this down to worn suspension bushes as it didn't seem gear/speed related. I have since checked the suspension and all seems fine.
Could this be a problem with the prop shaft - it really sounds like it's coming from there - does anyone know what I should check? Any suggestions much appreciated. Griff 500 96 with GKN (I think).

David

GreenV8S

31,017 posts

313 months

Thursday 9th January 2003
quotequote all

I am getting a clonking/clanking sound from aroud the diff/rear of the transmission tunnel. I have the car up on stands at the moment and have run the car in gear (at around tick over) 1st, 2nd & 3rd no noise, but 4th & especially 5th there is a pronounced clonking. I had noticed this before when driving but put this down to worn suspension bushes as it didn't seem gear/speed related. I have since checked the suspension and all seems fine.
Could this be a problem with the prop shaft - it really sounds like it's coming from there - does anyone know what I should check? Any suggestions much appreciated. Griff 500 96 with GKN (I think).

David


Is it all the time, or only when you switch between acceleration and overrun? Diff bushes seem to be a favorite cuprit for this.

dougal

597 posts

313 months

Thursday 9th January 2003
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Had the same thing on mine, it was a combination of diff bushes and the fact that the diff mounting plate had cracked and split. The clonk I noticed was speed related and at low speed.

davidn

Original Poster:

1,028 posts

288 months

Friday 10th January 2003
quotequote all
Peter and all, thanks for your reply's, it seems to be all the time. With the back up on stands I engaged gear and let the clutch out, not using any throttle, as I said fine in all but 4th and 5th. I haven't applied any throttle in this situation so cannot tell if the problem worsens or improves on overun or acceleration. However when driving the problem seemed to be evident most of the time which is why I believed it may be suspension related, I might not have noticed it so much in lower gears due to engine noise masking the clonking. I am going to get under the car and check the diff mounting bushes and plate for wear more closely but no chance of a road test at the moment because of the snow. If any of the above helps you shed any light on the problem I would be grateful to hear.
Thanks, David

heliox

450 posts

291 months

Friday 10th January 2003
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Heres one thing to check also,

have a look to see if the fuel tank is loose.

also, check to see if the rubber hose that is attatched to the tank and runs through the body and attatches to the fuel pump has enough flex in it as this sits on the wishbone and flexes as the wishbone travels up & down with suspension movement.

If its too tight it will lift the fuel tank slightly and give a bush like bang/bonk. Its difficult to see the movement in the tank as its covered by the boot carpet, the best place to look is where the hose runs through the body, Suspension needs to be loaded up to see this as when on jacks the wishbone hights are at their lowest.

hope this helps
heliox

davidn

Original Poster:

1,028 posts

288 months

Friday 10th January 2003
quotequote all
Thanks Heliox, I'll check the tank anyway but doubt this is the problem as the noise is more pronounced with car on axle stands and rear wheels turning under power, so probably no movement in suspension.
Thanks anyway. David.

GreenV8S

31,017 posts

313 months

Friday 10th January 2003
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Can you feel any roughness/unevenness with the car on stands, if you turn the wheels by hand?

dr chuff

296 posts

313 months

Friday 10th January 2003
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David,

I had the diff mount bushes go on my Chimaera 500. It clonked at take-up, but also with any suspension movement. Running your car on stands may only provide enough inertial resisitance in 4th, 5th to produce the clonk.

Hopefully it is this, as it's a cheap and easy fix.

Dr C

cockers

641 posts

310 months

Friday 10th January 2003
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dr chuff said: David,

I had the diff mount bushes go on my Chimaera 500. It clonked at take-up, but also with any suspension movement.

Hopefully it is this, as it's a cheap and easy fix.

Dr C



Dr C - approx how much? That sounds exactly like what's going on with my Chim at the moment.

Cheers,

Paul

davidn

Original Poster:

1,028 posts

288 months

Saturday 11th January 2003
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Peter,
I've turned the rear wheels by hand and whilst there is no gratting the R/H wheel is binding, pads seem to be the cuprit.
I have been under the diff with engine running in 4th and the diff clonks and shimmey's irregularly, more so in 5th slightly in 3rd nothing in 2nd or 1st. Diff bushes seem fine and not much movement on them, vibration appears to be from within the diff, prop shaft looks as if it is running true but R/H drive shaft does not seem totally true, I've tried pulling up and down on both but there is no play in either. I have run it up to aorund 50mph in 4th and vibration charchterstic's are much the same but I did notice that the R/H wheel stopped spinning in relation to the L/H and jerked round a quarter turn at a time but maybe this is the LSD reacting to the binding caliper?? Does this sound like a diff rebuild?
If anyone has any thought's I'd be grateful to hear.
Getting worried, David

pvdv

23 posts

252 months

Thursday 17th August 2006
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And what was the cause of this?