Just bought a 74 Bronco which I was told could be driven everywhere. I'm scared to drive it anywhere. It has a 3 1/2" - 4" suspension lift and it shakes and vibrates very badly from the rear of the vehicle. Does anyone have any tips/ideas for me? It does not have the factory cast iron rear end wedges which I was told it should have. Should these be used in conjunction with the lift blocks under the leaf springs?