Hi folks.

OK so it's christmas eve and you've all probably got lots more important stuff to do, but I need some help.

Today my XF has started making a thumping noise at low speed.
Comes from the rear of the car and is speed (wheel / tranny speed - not engine speed) dependant. I cannot hear it above 30 mph but that may because the tyre noise starts to drown it out, and you can still feel it a little up to about 40 mph.

Have checked the tyre pressures and all are at 29psi which I'm told is fine. There have been no bumps or bashes (unless the wife has had one which she hasn't mentioned, but there are no visibles).

I did get out of shape the other night on a tight bend but this was at less than 30mph and it only slid a little at the rear.

Anyone got any idea. I go on holiday on Wed 28th (400mile drive) so would appreciate any advice before then.

Happy Christmas to you all.
Steven