PSC SG840R Big Bore XD Cylinder Assist Steering Gear, GMC 2500/3500 4WD (88-98)

The factory steering on your late-80s to late-90s GM truck wasn’t built for today’s big tires and heavy-duty use. That’s where the BIG BORE XD Steering Gear comes in. With a beefed-up 45mm sector shaft, larger bearings, and an oversized piston, this gear delivers tighter steering, more torque, and way better control—on the road or off it.

Whether you’re running stock steering or adding hydraulic assist, PSC has got the right gear for your build.

This listing is PSC part number SG840R (Gear Type: Cylinder Assist).

Features

• Stronger Where It Counts: 45mm sector shaft and upgraded bearings eliminate deflection.
• Better Steering Feel: Variable ratio for easy parking and stable highway driving.
• Built for Big Tires: Increased torque output for heavy-duty setups.

Specifications

• Part Number: SG840R
• Gear Type: Cylinder Assist
• Turning Ratio: 13/16:1 (3.5 turns lock-to-lock)
• Input Shaft: GM DD with 3/4-30 spline adapter
• Port Type: Metric O-Ring
• Mounting: Inside-the-frame, 3-bolt pattern

Fitment

• GM 2500/3500 4WD (1988-1998)

What’s Included

• BIG BORE XD® Steering Gear (choose your option below)
• Mounting hardware

Options

• Standard BIG BORE XD® Steering Gear - Direct bolt-in upgrade for factory steering
• BIG BORE XD® Cylinder Assist® Steering Gear - Pre-drilled and tapped for hydraulic assist