The shackle should be the easiest way to drop a leaf truck 1 1/2 -2",& shouldnt cause any trouble......other than you may need a wedge type shim 'tween the axle& spring to bring the driveline angles on. I have been told the brass wedges are the best, & can be picked up in a 2 or 4 degree at the local spring shop. good luck.....Longhorn