2010 SC. I noticed last night in stop and go traffic as the driveline goes from slack to engaged against driveshaft there is an audible clunk. Wonder what is at play.....pardon the pun but it seems like there is too much play. All else is totally normal. Wonder if there is an adjustable lash in there somewhere?

 

If you are talking about the ZF thump, really more like a slight lurch as you roll to a stop and the transmission downshifts ready for acceleration, then they all do that to greater or lesser degree. The older spec ZF in the XK and XJ were notorious for this.

However, actual driveline lash may be a symptom of a bad differential. These can be adjusted but you might as well fit a new one as you have to remove it to re-shim it and the original fault resulting in the need to re-shim is likely going to cause failure. Jaguar specifies a running in period for the differential which for a used car might be a problem if the first owner did not observe this unusual requirement There was also a bad batch of these diffs replaced under extended warranty, caused by carborundum residue left in during manufacture causing premature wear. Your 2010 should be outside that VIN range so likely that isn't the issue with yours.

Finally, bad prop shaft could cause this. The XF uses carbon fibre prop shaft which is balanced by different spec securing nuts on the universal joints. Might be worth checking all is well there if you decide this is not just the ZF torque converte clutch thump.

 

No, I know the surge. This is slack in the diff or the drive shaft universals or something in that chain. Will have to have it looked at.

 

Again, I hope a direct link to the UK site is not rude:

XF Differential Backlash?

 

Yes I had seen that on the UK site prior. I could not replicate what was quite pronounced yesterday. Strange.

 

good luck let us know what they find. Could be too many donuts? or maybe not enough?

Does it do anything when your crusing, accelerate hard, then let up?
I have destroyed my fair share of Dodge 9.25 rear ends. It always started with a clunk leaving the light and then when the pinion bearing seized solid on the pinion gear shaft jerkyness under deceleration/coasting.

 

I get a clunk when the car is cold and I sart and then engage reverse but I think this may be caused by the brakes being on while in park, I noticed the lurching between 2-3 in slow traffic but no clunk heard then