Abstract: A post driver has a combination of hydraulically operable orthogonal and angular mechanical carriages giving five degrees of motion of the driving hammer for the setting of posts in various soils and terrain slopes. Adjustment of the carriages allows accurate location of posts in a fence line that is offset from the line of travel of the supporting tractor. The structure of the apparatus provides distributed weight to both sides of the tractor to assure its stability and safety for operations over variable terrain slopes. A post sleeve and holding bar contain the posts for hands-off driving and also provide means for overcoming post misalignment due to variable density and stony soils. A damping device is added to the impact hammer mechanisms.