I have an international 784 4x4 tractor with a zf front housing. I noticed about an inch of the axle shaft that goes into the differential on the right side was pushed out. Then I was using it and noticed the drive shaft that goes to the differential was slipping instead of spinning like it should. So I took the front axle out of the differential and 1/4 inch of the splines were wore down. So I put the shaft back in and pushed it all the way into the differential and when the wheel is turned and hits the stops it pushes the axle back out. Also I've noticed on some diagrams that on the right side there is a double universal joint and on my tractor I have a single. Also, the left side has a bigger universal joint than the right side that we're working on.