Loud clunking noise
 

Yesterday, I took my lad to school, all seemed OK, but after dropping him off, I noticed a loud clunking noise. It definitely wasn't apparent before I stopped at the school. It only seems to happen when the car is moving and increases as the car accelerates, and reduces as the car slows down.
I have since taken the car to my trusted mechanic, he has heard the noise, has checked things over, but is unable to find anything wrong.
The car is a 2007 e70 3.0d SE X5 with the sports pack. It is on 110,000 miles and according to the service history, and has been well serviced, I will have owned it for 3 years next March.
Just wondering if anyone has any ideas..... Diff maybe?

Sent from my SM-G981B using Xoutpost.com mobile app

Maybe transfer case issue?

Thanks for your reply. In your opinion, could the transfer case go wrong without any prior warning ? My mechanic phoned and asked if I had been on slippery ground and accelerated hard as I drove onto solid ground, which I haven't. The car has been driving great and has given no signs of there being a problem at all.

IIRC, some E70s have issues with the front drive shaft failing and the result can be quite destructive. But, the covers need to come off from under the car as the front drive shaft is only partly visible and rear one is (almost) completely covered. I'd also worry that, if you have an audible noise while driving, your mechanic should be able to diagnose it. If he can't, you need a new shop.....

Repeating clunking under power hints at driver train. Center support bearing or guibo first bet or a CV axle starting to fall. Can you tell where is coming from?

To me, it sounded to be coming from the drivers front (UK being RHD), but was hard to tell. Even though I am quite handy with the spanners etc, I don't have anywhere to work off road, I always use the same mechanic and went straight to him, dropped the keys in the office and left again. He is fitting me in between the other jobs that he already had booked in. He's an old school mechanic, who replaces the broken spring rather than the entire gearbox and charges accordingly.

If there problem is repeatable will be easy to find. If it's more of a top than a clunk (think Morse code but using a small hammer on metal), then it's almost assuredly the anti sway bar links.

This.


OP. Im all for saving money and getting that 'perfect diagnosis'... but if a driveshaft breaks it can take out your transmission...a $500 job turns into $7000 disaster (convert to GBP..)

Well, just goes to show how weird things can be. Everything has been checked thoroughly, the only thing found was in the rear diff, a slight bit of damage, but nothing that would be expected to cause a loud clunking noise as has been experienced. The rear plate has been put back and new oil topped up...... the noise has gone.
I am now following instructions and giving it a few days of normal use to see if the noise returns.

Sent from my SM-G981B using Xoutpost.com mobile app

Welp..the catastrophic failures dont tend to quite down, so probably not a dangerous plan....