Looks like a heavily modified Chevrolet G506 1-1/2 ton Army truck. The PTO control lever was typically located right in front of the seat, between the drivers legs. As many other modifications as this truck has, it may have been relocated. Looking at the body of the PTO, there will be at least one control rod, or two if it is a dual output PTO. As HotRod Lincoln indicated, I would also remove the shifter top cover, and see what shapr the gears are in. It is not unusual for trucks in Northern locations, and open and exposed to the elements to get water in the transmission. That usually binds up the gears, then when freezing weather comes, the freezing water cracks the case, allowing it to spill its guts when it finally thaws.
