I'm considering purchasing a 73 Ford 4000 diesel for a bushhogging tractor. Haven't looked at it yet but the guy says it runs great and has no issues other than "the 3 point doesn't work". He said the implement dealer told him it is probably a pin that came loose inside because it runs the PTO off the same pump. 
I'm pretty good with wrenching but don't have much knowledge of the hydraulics on these tractors. I don't mind a repair if I can get it for the right price, but would like a reasonably good diagnosis before buying it. Anyone know what might be the problem?

I'm pretty good with wrenching but don't have much knowledge of the hydraulics on these tractors. I don't mind a repair if I can get it for the right price, but would like a reasonably good diagnosis before buying it. Anyone know what might be the problem?