Revolution Gear and Axle, Replacement series, Rear axle shaft for Ford 9 Inch 74-86 F150 and E150, fits both Left and Right side, 32 Inch 31 Spline (OE# D6TZ4234A / Hollander# 447-1172). Revolution replacement series axles are made from 1541H Steel and utilize a state of the art computer controlled heat treated process. The use of better material and better heat treating process gives our replacement axles a 10 Percent increase over the OEM axles.