So yesterday I finally made it. Take off the left half shaft and take off the differential. As I disassembled everything I found that pinion is missing three claws, then a lot of the claws on the ring was also damaged but only two was cutted. One small ring was damaged also. Nevertheless as I saw the reason for this was probably big tires in a big offroading, then the claws on ring started to be damaged then some small piece of this went through the rest of gearing and damaged the rest..no other reason was visible.
Also this reason is supported by the fact that backslash between inner rings in diff and halfshafts was very big. Halfshafts are totally ok.
So I repaired that and use a Militac to enforce it.
Some pictures will follow.
Petr