1995 powerstroke wheels turn of camber when goin in reverse?

[Toddmichaud]

The other day I backed into a parking spot, and my friends noticed that once I started moving backwards my wheels turned off camber, inwards and back, but when I move forward they straighten back out again to perfect alinement.I think its some sort of bushing that needs to be replaced but im not sure so any help I can get will be much appreciated.