I have a 1965 Ford 4000 SOS 3 cyl gas struggling to turn over. I was pulling a stump out when I ran out of power and stalled the tractor. Would not restart, would not crank, starter was engaging, assumed I had a battery or starter issue. Tried with a jump pack, no help. Pulled the starter, seemed fine on the bench. Disengaged the driveline and pulled to the barn. That was a year ago. Now I've deceided to make an attempt to repair, but not sure where to start. I can manually turn the engine over backwards with the front shaft for the FEL hydraulic pump, but forwards it seems to be binding mechanically. Transmission or engine problem?