Got the gearbox off without any issues, and the gears that i can see so far look good, but I cannot get the output shaft nut to come loose.  I put a pair of vise grips on the small diameter of the shaft but I could not hold it tight enough to break the nut loose.  

 

In the instructions I downloaded it showed two nuts one locking the other, mine only has one nut and it has a nylon insert in it.

 

I, thinking I could take two pieces of aluminum and clamp them in the mill vise, then drill a 0.750" hole through the joint then drill and file a slot for a key way.  Then put the key in the shaft slot and using a crescent wrench to hold the pieces together on the shaft and also hold the shaft, I should be able to put enough pressure on the lock nut to get it off.  

 

This is the least invasive way I can think of, or is there a better, easier way?

 

Thanks