I have a TG 1860 about 7 yrs old, if you hit a bump the mower disengages and you have to hit another bump or wait @5 minutes and it will reengage. The engine dead man switch works correctly , what type os switch/sensor am I looking for.
Sounds like either your PTO clutch has a loose wire or its one the edge of going and needs to be replaced. Check for loose wires on the PTO clutch and see what you come up with. If its that bad where you have to wait 5 minutes, sounds like the clutch is geting hot and needs to cool down before working again.