So yesterday on the way to clinic my 2007XK started clunking, at first I thought it was a rear tire, but no warning light for pressure. Pulled over, all looked good.
Resumed my way to work and the clunking continued.
Downhill (coasting - off accelerator) it is definitely worse.
Accelerating not so bad.
Turning sharply and decelerating is the definitely the worse.
Not changes with brakes on, not a brake wobble, definitely a clunking.
Repetitive in synchrony, speed related, not RPM related, gearing does not seem to matter much.
Had my wife do a drive by accelerating and decelerating, I could not hear it from outside the car.
Can definitely hear and feel it inside the car.
Diagnosis time, my suspicion is rear differential. I am a backyard mechanic and can do many things myself, so help me figure this out.
If it is the rear diff, I am not tackling that job and will definitly have a shop do the repair for me.
All advice is appreciated, for now, she is parked until I get an answer.

 

Check it this way... with the brake on and engine running, shift from D to R, then back again several times. Could be the diff or the CVs on the prop shaft. Or even the rear half-shafts.

 

What am I looking for when I go from D to R?

 

I felt nothing unusual, no clunks, no sounds, just a normal shift.

 

Maybe a wheel bearing? Try jacking up the car, and spinning each wheel by hand, see if you hear, or feel anything.

 

Don't think its a wheel bearing, I would have heard it when she drove by.

 

Sorry; you'd hear that clunking if the prop shaft CVs were gone, and possibly if the diff/ring and pinion were trashed as well as the half-shafts.

 

ON the 100 models that noise can be a shock mounting point.

 

So how would you go about figure out what it is?

 

How fast do you need to be going to hear/feel the clunk?
Maybe lost a wheel weight? And now have an unbalanced wheel?

 

Definitely not wheel balance, it is noticeable at all speeds, more pronounced at higher speeds, at a regular interval, worsens when off the accelerator.

 

And if you shift into N?

 

Mine started clunking yesterday. Like something was rolling around in the trunk behind rear passenger seat. Mine is intermittent.

 

Remember always check simple things first! shock mounts, muffler system, ujoints (jack up rear end; check for play in drive train) run engine and listen; always use axle stands for safety!!!
On & off throttle may help you hear something amiss & where.

Good luck , Adrian

 

Had same issue/sound on my Beemer. More likely a rear axle than the driveshaft, and if it is do both now as you will be doing both anyway.

 

Once you do your due diligence, shock mounts, loose exhaust hangars etc and you find all to be tight, or not worn, then I would say its something in your driveline.