I pulled apart my '79 F150's Dana 44 and found a plastic spacer/gasket/shim, or whatever it is, between the spindle and the steering knuckle. I didn't notice until after I had taken them off, both passenger and driver side had one, and examined them later that one side of the plastic circle was about twice as thick as the other side and they were both marked with the number "4." I don't know how it is supposed to go back on; thick side to the front or rear of the truck? I called two drivetrain companies and neither knew what I was talking about. Is this some kind of caster/camber adjustment done by a front end shop or maybe by the factory when it was sent out the door? Thanks for any help!

 

It's a camber shim. The shim should go with the thick part closest to the wheel or toward the axle. You'd have to remember which way it came out. There is no other way to adjust the camber - the rest of us just rotate the tires frequently to prevent the abnormal wear associated with running positive camber. It's much worse on TTB's!! I would guess the thick part goes toward the wheel - but I'd have to see the truck.

 

The thick part should go either on the top or bottom. It should only go one way since the holes won't line up any other way.