Assuming it is all stock the first place I would look is the axle shaft u-joints. If one or both are bad they will start binding and bucking the moment you turn the wheel on pavement. The only other cause that I can think of would be a locker or welded spiders.
1981 Jeep CJ7 4.0 HO, AX-15, D300, D30, D44, SOA
1977 Chevrolet C/10 step side 454 TH400 3.73 posi