Now that it has cooled down, the shaft which goes to the gearbox turns remarkably easy. And, as so noted once I reconnected everything it worked fine.
Or maybe, the fluid needs to be changed, that is if you can, and are supposed to change it.
Heavy Duty gear oil or Part# 350572 is 16oz gearcase oil. The guy's transmission probably needs Part# 388253 Neutral Pak.