Help with transmission in GT

Hi all, Im new to this thread, being a Massey guy, but I need some help with my grandfather's 1973 Montgomery wards garden tractor made by the Gilson company. It is a 16 hp with a gear transmission and variable drive belt. The problem is that the transmission when in any gear will just grind and it goes nowhere. He says that this happened before, and the guy that fixed it said it was the "torque spring". It was going fine and then it just stopped.
Also, does anyone have any idea about freeing up the variable drive, since it is stuck, and if anyone has a useable hydrualic pump for this tractior that does not leak, it would be very helpful. It is a century fox pump with a spool valve built into it. Thanks in advance for any help.