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BIG BORE XD® Steering Systems - RAM 4500/5500 Diesel (2017-2024)

BIG BORE XD® Steering Systems - RAM 4500/5500 Diesel (2017-2024)

$1,195.00
$1,195.00
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Part Number: SG859

Type

Heavy-duty trucks need heavy-duty steering—and that’s exactly what PSC’s BIG BORE XD Steering Gear delivers for your RAM 4500 or 5500. Whether you’re hauling, towing, or working your truck hard every day, this gear is built to handle it without breaking a sweat.

The SG858 series is 100% brand new (no core charge), and it’s a direct replacement for Mopar 68236674AD. It’s tuned with PSC’s ported and balanced valving for smoother control and better road feel, even with oversized tires or heavy loads.

Want even more muscle? The Cylinder Assist version adds hydraulic power to help turn those big tires like they’re stock—especially handy when you're loaded down or off-road.

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PSC TRAIL SCORE

5/5

Extreme Off-Road

Engineered for the toughest trails and extreme rock crawling.

About:About:

Why you’ll love it

  • Built for big diesel trucks – no more sloppy steering
  • No Lane Assist? No problem – works with traditional setups
  • PSC-tuned valving – smoother, more confident control
  • Cylinder Assist option – extra turning power when you need it
  • 100% new – no core charge, no rebuilds

Tech InfoTech Info

Heads‑up for installers

This gear is designed for non-Lane Assist RAM 4500/5500 trucks. It’s not compatible with factory torque overlay systems. Both versions bolt up to factory lines and pitman arms. Always flush your system before installing new components, and check your pitman arm fitment if you’re running aftermarket steering.

Fitment

  • RAM 4500 & 5500 Diesel (2017–2024)
  • 2WD and 4WD models
  • Not compatible with LaneSense Lane Departure Warning
  • Not compatible with factory torque overlay systems

Use it with

  • RAM 4500/5500 Diesel trucks (2017–2024)
  • PSC high-performance pumps and remote reservoirs
  • PSC Cylinder Assist® axle kits (for SG858R)

Ideal for

  • Commercial and fleet trucks 
  • Heavy-duty towing and hauling 
  • Drivers who want stronger, more responsive steering 

Specs

  • Steering Gear Models: SG858 (standard), SG858R (Cylinder Assist)
  • Sector Shaft Diameter: 45mm
  • Internal Piston: 80mm
  • Steering Ratio: 16:1
  • Valving: PSC ported, balanced, and tuned
  • Compatibility: Non-Lane Assist, no torque overlay
  • Finish: Black Painted Casting

What’s included

Choose from: 

  • BIG BORE XD Steering Gear (SG859)
  • BIG BORE XD Cylinder Assist Steering Gear (SG859R) 

SupportSupport

OEM Cross Reference

  • Mopar 68236674AD Direct Replacement - SG859R
  • Mopar 68236674AD Direct Replacement - SG859
California Prop 65 Warning

California Prop 65 Warning

This product can expose you to chemicals including lead and di (2-ethylhexyl) phthalate, which are known to the State of California to cause cancer, birth defects or other reproductive harm.

For more information, go to www.P65Warnings.ca.gov