I am trying to remove the lead screw on a G0768 and while the manual diagram shows the left side held in place by shaft and key, I cannot easily budge it. I don't want to pull too hard for fear of damaging something. This is the portion to the left of the shear pin that goes into the gearbox. I want to get at the ball bearing on the outside of the gearbox for lubrication/cleaning as I am in the process of re-building a new unit and want to leave no part neglected. The coupler sleeve to the left of the coupler can't be freed until the screw is removed. The first few photos here: https://photos.app.goo.gl/DWD8L5AH8G4rGNxc8 show what I am looking at.