The New BIG BORE XD JK steering gear is the most powerful and strongest replacement Jeep JK steering gear on the market. Anyone with a Jeep JK running large tires and/or has a locking front differential will want this bolt on upgrade on there must have list. The BIG BORE XD produces up to 35% more turning force than the OE steering gear. By replacing the stock 70mm piston assembly to a larger 80mm piston, output torque is increased significantly. This is the same piston assembly found in all new Ram 2500/3500 diesel trucks. The increased turning torque will turn up 37" tall tires without the need of cylinder assist. Changed also is the sector shaft diameter. This has been increased from 35mm to 45mm to handle the extra torque output. Included in the kit is a new pitman arm that mates to the larger sector shaft. Note the pitman arm is a OE replacement and has no extra drop to it. The BIG BORE XD was engineered for use of a high-pressure pump-1800 PSI. PSC highly recommends the use of their HIGH FLOW/PRESUURE pump kits designed for BIG BORE XD applications. These pumps operate at 1800 psi and produce 50% more volume per revolution than the OE pump. The factory OE steering pump operates at 1500 PSI and will operate the system, however you will not be benefiting from the full potential of the steering gear. Steering could feel worse if your OE steering pump has been overheated or has high mileage. Always use a power steering fluid cooler and PSC recommended power steering fluid.