Product Description
Upgrade one of the most notorious weak points in the GM HD steering system with the PSC SG039R Big Bore XD Cylinder Assist Steering Gearbox. Built specifically for heavy-duty GM 2500HD and 3500HD trucks, this steering gearbox features PSC’s legendary BIG BORE XD architecture designed to eliminate steering slop, shaft deflection, and premature seal failure commonly found in factory steering boxes. Unlike factory units or remanufactured steering boxes, the PSC SG039R is engineered from the ground up for performance applications including lifted trucks, oversized tires, towing setups, and off-road builds. The oversized 45mm sector shaft dramatically improves strength and steering feel while the upgraded roller bearings prevent shaft deflection under heavy loads. This version of the PSC XD gearbox comes ported for hydraulic cylinder assist steering systems. The assist ports are capped from the factory so the steering box can be installed on standard steering setups today and upgraded to PSC ram assist later. Whether you're building a heavy-duty tow rig, rock crawler, or high-performance diesel truck, the SG039R is one of the most trusted steering upgrades available.
Fitment
- 1999.5-2006 Chevrolet Silverado 2500HD 4WD
- 1999.5-2006 Chevrolet Silverado 3500HD 4WD
- 1999.5-2006 GMC Sierra 2500HD 4WD
- 1999.5-2006 GMC Sierra 3500HD 4WD
- Designed for trucks running large tires, lift kits, or heavy-duty towing setups
- Compatible with PSC hydraulic cylinder assist steering systems
- Requires PSC PA806 4-Spline Pitman Arm for installation
Specifications for PSC SG039R
| Specification | Details |
|---|---|
| Manufacturer | PSC Steering Components |
| Part Number | SG039R |
| Series | Big Bore XD |
| Sector Shaft Size | 45mm |
| Steering Assist Ports | Yes (Cylinder Assist Ready) |
| UPC | 687927185906 |
| GTIN | 687927185906 |
| Shipping Info | Calculated at checkout |
| Prop 65 | WARNING: Cancer and Reproductive Harm – https://www.P65Warnings.ca.gov |
Frequently Asked Questions
What makes the PSC SG039R better than the factory GM steering box?
The PSC Big Bore XD steering box uses a larger 45mm sector shaft and upgraded bearings that prevent the shaft flex and seal failures commonly found in factory steering gearboxes.
Does this steering box support hydraulic ram assist?
Yes. The SG039R is pre-ported for PSC hydraulic cylinder assist steering systems. The ports come capped so the steering box can also be used with a standard steering system.
Is this a remanufactured steering gearbox?
No. PSC Big Bore XD gearboxes are built with upgraded internal components designed specifically for high-load steering applications rather than remanufactured factory units.
Do I need a different pitman arm for installation?
Yes. PSC recommends using the PA806 4-Spline pitman arm when installing the SG039R steering gearbox on GM 2500HD/3500HD trucks.
Will this help with loose steering on lifted trucks?
Absolutely. The stronger sector shaft and improved internal components help eliminate steering play commonly experienced on lifted GM HD trucks with larger tires.
