Kraton Kraton 6s v5 diff problems again

[BO55_Saint]

Took my kraton out for a quick run and could hear a slight crunching when braking. I feel its the rear diff so I put the car on the stand and then found the strangest thing.
If I turn 1 front wheel, the other one turns in the other direction as it should, but if I turn one of the rear wheels, all 4 turn.
Anyone knows why that is happening?

 

[Neelis]

Probably resistance on the inside of the rear diff or a stuck wheel bearing on the other rear wheel.

 

[332_RC]

Broken teeth on the satellite or sun gear or both in the rear diff. It's locked up.