Monroe 34811 Shock Absorber - Rear

Monroe Gas-Magnum Rear Shock Absorber

The Monroe Gas-Magnum Shock Absorber 34811 is built for midsize and full-size trucks and vans that need firm rear suspension control without an overly harsh ride. It is a fitment-based replacement for heavy-duty applications, including Chevrolet Silverado 2500 HD, Chevrolet Silverado 3500 HD, GMC Sierra 2500 HD, and GMC Sierra 3500 HD rear suspension setups.

The Gas-Magnum line is Monroe’s heavy-duty shock absorber family for larger vehicles. This design uses greater fluid capacity than a standard 1-inch bore shock, helping the shock work with less effort and maintain consistent damping under load.

• Rear shock absorber for heavy-duty truck and van applications
• Designed for firm control with a controlled ride quality
• Up to twice the fluid capacity of standard 1-inch bore shocks
• Dust shield included for added protection
• Extended bumper stop included; compressed bumper stop not included
• Upper and lower loop bushing and sleeve mounts
• Upper and lower mounting code: LS47
• Compressed length: 16.21 in.; extended length: 25.32 in.; travel length: 9.11 in.

Fitment Details

Compatible With rear applications on the following vehicles:

• Fits 2020-2025 Chevrolet Silverado 3500 HD, rear.
• Fits 2020-2024 Chevrolet Silverado 2500 HD, rear.
• Fits 2020-2024 GMC Sierra 2500 HD, rear.
• Fits 2020-2024 GMC Sierra 3500 HD, rear.
• Fits 2011-2019 Chevrolet Silverado 2500 HD, rear.
• Fits 2011-2019 Chevrolet Silverado 3500 HD, rear.
• Fits 2011-2019 GMC Sierra 2500 HD, rear.
• Fits 2011-2019 GMC Sierra 3500 HD, rear.
• Fits 2014-2018 Chevrolet Silverado 2500, rear.

What This Shock Absorber Helps Address

• Excessive rear-end bounce on heavy-duty pickups
• Reduced control when towing or carrying payload
• Harsh or inconsistent damping from worn rear shocks
• Rear suspension instability over rough pavement
• Ride quality loss in high-mileage truck applications

Installation Notes and Tips

Verify the upper and lower mounting style before ordering, since this Monroe 34811 uses a loop bushing and sleeve mount with a 9/16 in. sleeve ID and 1.5/8 in. sleeve OAL. Confirm compressed length, extended length, and travel against the vehicle’s rear suspension dimensions to ensure proper fitment. This part cross-references Rancho RS55379 for the same application.

Quality Assurance

Monroe Gas-Magnum shocks are engineered for heavy-duty rear suspension service and are backed by Monroe’s limited lifetime warranty on the 2011-2019 Silverado and Sierra applications listed above.