Today I was driving my kubota L 2950 GST backwards in (4 th gear 1000 rpm) when all of a sudden, the engine stalled almost as if the transmission locked. I restarted the tractor and it did not go frontwards or backwards. It seems like it is always in neutral. I can put the reverse and put it in any of the 8 gear and it does nothing at all. If I press on the cluch and shift, once in a while, it will kind of lock and the engine would stall if I tried to fully release the clutch. Does anyone have any idea of what the problem could be?