I recently had a leak on a rear akle seal on one dide of my rear diff on a2008 jaguar xj-r.

I had that fixed 3 weeks ago. Driving on the highway last night and ever since I hear this weird noise form the back of my car that starts when I accerale over 30mph and chages pitch in the sound when i drive faster or slower. Sounds like a street bike is follwoing me.

Is this from the differential or something else? What does a rear sdiff noise make ? They looked at the bearings and said one had some play but it was very minimal. Car has 103k on it. Any help?

Any links to where I could buy a used one for a 2008 JXR? new ones ar $6,000