help: clonking while driving - diff not ok?

[350zwelgje]

Thought I identified the cause of the clocking I have: one of the halfshafts.
Taken from the car, it would not rotate freely: wheelbearing not ok.
Replaced now, but still a clonking while driving and in a straight line at constant speed and at low speeds during sharp cornering....

There is nearly no play in the half- and propshafts. Think the U-joints are ok.
To me it seems the play/backlash in the driveline and diff is the same as I had for years.
Could the clonking be caused by the diff?

If so that would not be so great as next weekend the wedge is entered in a classic rally (it is tourist class only) and going to meet the pistonheader at 11 May (the W day).

Any good news is welcome.

Rob

[Wedg1e]

Propshaft UJs, diff top support beam fractured, gearbox mounts broken, exhaust hitting something, diff mounting rubbers shot... but most likely the half-shaft UJs even though you can't feel any play in them. I test by running one side wheels up on a kerb, then lie underneath the rear while someone 'bounces' the clutch pedal around its biting point (handbrake on). If the UJs move, you will see it.

[mrzigazaga]

I had s clonking type of noise/feel on my 280 when i use to de-accelerate ...It felt a little like an auto clonking in to first gear at idle..Im sure that it turned out to be a broken UJ on the propshaft...I will have to check my previous posts...Ziga

[pasogrande]

Rob,

In addition to the other suggestions, try to find a place where you can drive parallel to and close to a wall. With the window down you may be able to locate the sound better. Then repeat with a passenger on that side.

This simple method has helped me a few times. Trouble is you may hear some new noises!

Wilf.

[Yatesy350i]

Get it nice on secure on a ramp/lift if you can. And then run it but not to hard just in case. That's how I identified my off side driveshaft UJ had gone. Thought the noise was coming from elsewhere until I got it in the air.

Karl

[mrzigazaga]

Mine was the propshaft UJ..I just found the post!...
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

[350zwelgje]

Thank you for the replies.
Will have think in what sequence I will check, test.
It then will be the last thing of coarse to detect it ;-)

Rob

[bluezeeland]

Hi Rob,

If you need a hand, ring, happy to assist......

Frank