Clunk Clunk noise ..Getting worse!

[Jazman]

Hi All,

Hope youve had a good summer! ... mine was going really well with the Chim until recently.. it started with a little thud when changing gears in the bottom/middle of the car underneath the gear section (but more to the rear).. and it gradually became more frequent.. to the point where it is now clunking all the time.. except when I put my foot down???.. the thuds are especially heard when in neutral when I let the car roll its a continuous thud, thud, thud ..more frequent thuds the faster I am travelling.. which slows down gradually when the car slows??

What could this be..ive had it on the ramp and its not the exhaust.. one theory its the Dif or Div (sorry for the spelling..doh!) mount/shaft which is loose.. could it be dangerous?? it doesnt effect the performance?

Its driving me mad!!..and now its getting louder...agh!!! ..now is not the time for any major problems due to redundancy ...eeeek!! Fingers crossed!

[zippee]

Get your diff mount bolts checked ASAP as they may be loose, especially if the noise has come on all of a sudden.
Mine also clonks quite badly and is because the diff bushes are split, been told it'll be OK till the next sevice in 2000 miles. BUT get an expert opinion on this as it can lead to a whole host of other expensive problems if not sorted/checked out.

[Jazman]

Thanks Zippee..

Im quite concerned now.. as its been happening for the last 2 weeks at least.. but I was just been a lazy git.. damn!.. what can else can it lead too?? Also is it expensive?? I heard the parts are cheap but the Labour can be up to 4 hrs!!

[zippee]

Diff bushes are about £250 fitted - pig of a job so I'm told.
Can lead to a lot of wear on other parts of the drivetrain, though afraid I'm not the most mechanically minded person so can't be too specific.
Take it to your local indie tomorrow and ask if they'd just take a quick look. Should take only 5 mins on a ramp.

[Jazman]

Just called em and ive booked it in.. but its next week.. and I really needed the motor this weekend..sods law!

Thanks Zip.. ill let you know what the issues were late next week.. fingers crossed he doesnt find anything else up there..

[Slacey]

I had a similar issue and hoped it would be the diff bushes - it wasn't. The diff itself was the problem - it never whined but there was enough wear in the bearings to increase the backlash enough for the unit to clunk as it took up drive. It will probably run on and on like that before a total failure but I'm having Bernie rebuild a replacement next week hopefully.

[hut49]

Jazman said:

... it started with a little thud when changing gears in the bottom/middle of the car underneath the gear section (but more to the rear).. and it gradually became more frequent.. to the point where it is now clunking all the time.. except when I put my foot down???.. the thuds are especially heard when in neutral when I let the car roll its a continuous thud, thud, thud ..more frequent thuds the faster I am travelling.. which slows down gradually when the car slows?? Fingers crossed!

As an alternative: transmission play and clunking can indicate a worn prop shaft UJ or a drive shaft joint. As you mention its a continuous clunking that varies in tempo with road speed, I think this is more likely than failure of one or more diff mountings. Anyway hope it turns out to be the most economical of the possible causes to fix.

[barreti]

Odd this, because I've just posted this similar advice on a different thread.

Your problem sounds exactly like the symptoms on my LandRover when a propshaft UJ was on its way out. Simple to replace really and didn't cost much.
When the UJ wears out it gets sloppy. When you accelerate the torque tightens everything, and the same when you are under engine braking. But in neutral it is just the wheels turning the prop so there's no tension.
The normal test for UJ failure is to get under and stick a big screwdriver in the gaps and try to lever it around, any play and it is shot. Try thoroughly greasing it through the grease nipple. If it quietens down for a short while you've found your culprit because the grease will give the joint and bit of tension (only for a short while though)

[GreenV8S]

See whether the noise is occuring at prop shaft speed or wheel speed - that will tell whether it is coming from the back axle/diff or from the diff/prop shaft.

[barreti]

GreenV8S said:

See whether the noise is occuring at prop shaft speed or wheel speed - that will tell whether it is coming from the back axle/diff or from the diff/prop shaft.

I know I'm being thick Peter but I'll ask it anyway.
How do you do this test?

[hut49]

barreti said:

Odd this, because I've just posted this similar advice on a different thread.

Your problem sounds exactly like the symptoms on my LandRover when a propshaft UJ was on its way out. Simple to replace really and didn't cost much.

....except on a Chimaera you may have a reluctant exhaust between you and dropping the prop, which substantially adds to the time and jacks up the cost