There is a retainer ring on the end of the pump drive shaft. The back part,with the gears in it,should just pull off after removing ring. As you're looking at the 2 front gears,the one on the left is keyed to the shaft,one on the right is like an idler gear and will slip out. Same for the 2 gears on the back side. There is the drive gear inside the gear cover, where cam is at, it also has a retainer ring.It keeps the shaft from coming out of the motor/gear case. You have to allign the pump for no drag when reinstalling. Good luck