PSC SG688R Big Bore XD Cylinder Assist Steering Gear, Jeep Wrangler JK/JKU (07-18)

The stock JK steering box? It’s fine for stock tires and errands. But throw on 37s, a locker, and a weekend in Moab, and that thing’s begging for mercy. The BIG BORE XD is the fix—built with a beefy 45 mm sector shaft and a reinforced case so it won’t twist, crack, or cry when you crank it hard. Pair it with a PSC High-Flow Pump Kit and you’ll feel the difference the first time you turn the wheel—smooth, strong, and no more arm wrestling at the trailhead.

This listing is PSC part number SG688R (Do you want Cylinder Assist® Now for Future Plan?: Yes).

Features

• 45 mm sector shaft - nearly 30% bigger than stock for serious strength
• 16:1 ratio with 80 mm piston - more torque, better road feel
• Includes PSC proprietary Pitman arm
• Bolt-on upgrade - fits JK/JKU with factory mounts
• Handles 35s without assist - and Cylinder Assist® makes it unstoppable

Specifications

• Part Number: SG688R
• Do you want Cylinder Assist® Now for Future Plan?: Yes
• Sector Shaft: 45 mm (stock is 35mm)
• Gear Ratio: 16:1
• Piston Size: 80 mm
• Ports: Metric O-ring (PSC includes adapters in kits if needed)
• Case: Reinforced mounting pad and housing
• Weight: ~57 lbs
• Includes: PSC proprietary Pitman arm

Installation Notes

• Ideal for: JKs on 35s-40s, Rigs with front lockers or heavy bumpers/winch setups, Daily drivers that double as weekend trail rigs, Builders planning for Cylinder Assist® down the road
• Recommended for: PK38JP1 - High-Flow Pump Kit for 3.8L JK, PK36JP1 - High-Flow Pump Kit for 3.6L JK, PSC Cooler and Inline Filter (always a good idea on big steering systems), PSC Cylinder Assist® Kit for JK (if you’re stepping up to 40s or hardcore trails)

Fitment

• 2007-2018 Jeep Wrangler JK & JKU
• Direct bolt-on for factory steering gear location
• Works with most aftermarket track bar braces (see bolt note above)

What’s Included

• BIG BORE XD® Steering Gear (SG688)
• PSC proprietary Pitman arm