Oliver 770 Roosa master Stanadyne pump removal question

[stevewatr]

Hello, I am having trouble removing the gear from the pump drive shaft. I was able to remove the pump because the whole gear/shaft assemblly slid out the front, but I know during re-assemblly, in order to be sure the umbrella seals go in correctly, I think I need to insert the shaft into the pump first, then install the pump, but because the tractor gear does not fit through that hole on the back, I think it has to come off. There were two bolts going through holes in the gear, they appear to help index the gear to the shaft, then there is a large nut on the end of the shaft, but it will not budge. The only way to hold the shaft, is by the tang on the end. I'm worried I might snap the shaft at the skinny part. Is there a trick to removing this nut??

[stevewatr]

A nice guy on Yesterday's tractors forum advised holding it with a rag, and useing an impact wrench.....It worked great.