Vince, it's simple gravity. The oil level in the gearbox is higher than the oil in the engine oil pan. when the seal let go, the two levels tried to equalize.
As far as who should have taken care of the problem, it was definitely Massey Ferguson who screwed up here. They should have backed up their product and paid the dealer to fix the problem. The dealer here also bears some responsibility if this happened with so few hours of run time after the purchase.
I think if it were me, I would try to find out who owned the tractor before I bought it to see what he experienced while he had the tractor. I have a sneaky suspicion that this may have happened before and may have contributed to the tractor being traded in the first place.
Seal's can leak at different rates depending on ambient temperature. The colder it is the more it will leak and the warmer it is it will leak less. I don't remember if dates were given in the original post of when this occurred and I could be barking up the wrong tree, but a pinched seal will always leak a little, especially if the vent tube is blocked or there is positive crankcase pressure. Since the hydraulic oil went into the engine, the pressure was in the tranny case and pushed the oil into the engine.
One other thing about shaft seals, they are cupped on the side facing the oil or any foreseen pressure. This actually forces the seal against the shaft as pressure rises to increase the quality of the seal. Pressure from outside the seal can pretty easily bypass a seal that is meant to keep oil in and contaminates out, which is the type normally used for a rear main seal.
But, all speculation on the cause aside, this was a MANUFACTURERS flaw and the MANUFACTURER should have paid for it.
Just my opinion
Nailerguy
