Cardone 27-7539 Remanufactured Power Steering Gear 100% computerized hydraulic testing is performed for proper flow, leakage and performance to ensure perfect fit and function All critical components (i.e. campacs, spool valves, etc.) are triple tested to ensure product reliability All units are built with 100% new seals and o-rings Sector shafts and pistons are 100% processed to ensure surface finish is within O.E. tolerances Hoses should be replaced if they appear brittle or if there are any kinks or leaks. The difference is the orientation of the teeth on the pitman shaft and power piston. Variable teeth will have a faster ratio than non-variable teeth. In a standard rotation gear box, the input and pitman shaft rotate in the same direction. The shafts turn in opposite directions on a reverse rotation gear box.