Nissan Primera P11 - differential (gearbox) issue

Guys...yet another problem with my 2.0TD Primera.

After getting out of some mud on a hill (took me a few minutes to get it going) i got this whining/grinding/clonking sound while i engine break. One wheel was on pavement, other one it the mud and it would slip until i managed to get free. But it really wasn't anything severe.

If i'm accelerating then i can't hear the sound, i also can not hear it when i put the car in neutral (still rolling).

The strange sound decreases when vehicle speed is decreasing (while engine braking). After checking some youtube videos and googling, i have come to the conclusion the issue is the differential.

What do you think? Has anyone had this issue before?

I'm having such bad luck lately...until 200 000km the car was amazing. From 200000 to 230000, i have change half of the car already...