1999 XJ 2.5TD weird rear differential noise
 

Hi all,

a little while ago I started noticing this weird "popping" sound that appears to be coming form the rear differential. This happens only when slowly reversing and mostly when turning whilst reversing and moving very slowly. Touching the tire (on either side) some kind of vibrations can be felt.

It also occasionally happens when moving forward if there is a lot tension on the drive train like starting up a hill. Also, it only appears to happen once the car has been driven for a little while and is "warmed up". Never happens when car is "cold". There are otherwise no other noises coming from this differential / rear end when driving forward at either slow or fast speed.

I changed the rear diff oil at 192,000 km. The car is now at 215,000 km, so roughly 23,000km since oil change.

https://youtu.be/N8C4uumOqbw

https://youtu.be/jHlnrfStFWk

Any ideas? I haven't opened the differential cover yet to see what condition it is in.