PSC Motorsports SG688R Big Bore XD Cylinder Assist Steering Gearbox for Jeep Wrangler JK

The PSC Motorsports Big Bore XD Cylinder Assist Steering Gearbox is engineered specifically for extreme off-road duty and represents a significant upgrade over factory steering systems. This precision-manufactured gearbox is designed to handle the increased torque demands of lifted Jeeps running larger tire sizes, heavy-duty axles, and locking differentials.

Enhanced Performance Features:

• Upgraded 80mm piston assembly (compared to 70mm factory) with 16:1 ratio for dramatically increased torque output
• Reinforced 45mm sector shaft (up from 35mm stock) provides 35% increase in strength to prevent shear in severe environments
• Integrated cylinder assist ports machined into the housing for seamless hydraulic assist integration
• Capable of turning tire sizes up to 37 inches with proper setup
• Strengthened mounting pad and reinforced case construction for extreme durability

Complete Kit Includes:

• Big Bore XD steering gearbox with cylinder assist ports
• Proprietary XD-JK Pitman arm designed for the larger sector shaft
• Mounting hardware (nut and washer)

This gearbox delivers improved on-road driving characteristics and significantly enhanced steering control both on pavement and trails. Built for enthusiasts who demand reliable performance in challenging terrain, the Big Bore XD requires a high-flow 1650 PSI power steering pump for optimal performance and longevity. Pairing with a fluid cooler is strongly recommended to prevent pump failure under extreme conditions. Backed by PSC's 1-year limited manufacturer warranty covering defects in materials and workmanship.