Product Description
Upgrade your Jeep JK steering system with the PSC SG688R Big Bore XD2 Cylinder Assist Steering Gearbox, engineered specifically for high-stress off-road environments and oversized tire applications. The PSC Big Bore XD2 series is widely considered the strongest replacement steering gearbox available for the 2007-2018 Jeep Wrangler JK platform. Designed to handle increased steering loads from large tires, locking differentials, and aggressive off-road terrain, the SG688R delivers significantly improved steering control, durability, and torque output compared to factory gearboxes. Featuring PSC’s exclusive Ram Port Tower with -6AN ports for hydraulic assist integration, the SG688R allows easy connection of a PSC steering assist cylinder for extreme off-road steering control. The oversized 85MM piston increases steering torque output by roughly 35 percent compared to OEM steering gears, allowing drivers to confidently turn 37-inch tires in harsh terrain. Reinforced mounting pads, a massive 45MM sector shaft, and heavy-duty case construction provide the strength required for rock crawling, trail rigs, and overland builds. Each PSC Big Bore XD2 gearbox includes a proprietary pitman arm designed to match the upgraded sector shaft, ensuring proper steering geometry and durability under heavy load conditions. For optimal performance and longevity, PSC recommends pairing this gearbox with a high-flow 1650+ PSI power steering pump and fluid cooler.
Fitment
- 2007 Jeep Wrangler JK
- 2008 Jeep Wrangler JK
- 2009 Jeep Wrangler JK
- 2010 Jeep Wrangler JK
- 2011 Jeep Wrangler JK
- 2012 Jeep Wrangler JK
- 2013 Jeep Wrangler JK
- 2014 Jeep Wrangler JK
- 2015 Jeep Wrangler JK
- 2016 Jeep Wrangler JK
- 2017 Jeep Wrangler JK
- 2018 Jeep Wrangler JK
- Fits both 2-Door and 4-Door JK/JKU models
Specifications for PSC SG688R
| Specification | Details |
|---|---|
| Manufacturer | PSC Steering Components |
| Part Number | SG688R |
| Steering Ratio | 16:1 |
| Piston Size | 85MM Big Bore |
| Sector Shaft Diameter | 45MM Heavy Duty |
| UPC | 687927184657 |
| GTIN | 687927184657 |
| Shipping Info | Calculated at checkout |
| Prop 65 | WARNING: Cancer and Reproductive Harm – https://www.P65Warnings.ca.gov |
Frequently Asked Questions
What makes the PSC SG688R better than the factory Jeep JK steering gearbox?
The SG688R features a much larger 85MM piston and stronger 45MM sector shaft which increases steering torque by roughly 35 percent compared to stock gearboxes, allowing easier steering with larger tires.
Does this gearbox support hydraulic steering assist?
Yes. The SG688R includes PSC’s Ram Port Tower with -6AN ports designed for easy integration with PSC hydraulic steering assist cylinders.
What tire sizes can this steering gearbox handle?
The PSC Big Bore XD2 steering gearbox is designed to handle tire sizes up to approximately 37 inches without assist and even larger when paired with hydraulic assist steering systems.
Does this gearbox require additional upgrades?
PSC recommends pairing the gearbox with a high-flow power steering pump capable of 1650+ PSI and installing a steering fluid cooler to prevent overheating during extreme off-road use.
Is installation bolt-on?
Yes. The SG688R is a direct bolt-on replacement for factory steering gearboxes in 2007-2018 Jeep Wrangler JK models, though some aftermarket track bars may require minor clearance adjustments.
