KYB 554388 Shock Absorber - Rear

KYB Gas-a-Just Rear Shock for Super Duty Trucks

The KYB Gas-a-just 554388 is a rear monotube shock absorber built for Ford Super Duty applications that need firmer control than a standard twin-tube design. It is engineered for trucks that work, tow, or run larger wheels and tires, while still maintaining a controlled ride in normal driving.

Gas-a-Just Line Overview

KYB Gas-a-just shocks use a high-pressure monotube layout with separate gas and oil chambers. That design supports quick response, consistent damping, and reduced fade during repeated suspension movement. For Ford F-250 Super Duty and Ford F-350 Super Duty rear applications, the Gas-a-just line is aimed at restoring control where load, towing, and road input demand more from the suspension.

Key Features

• Adds up to 25% more damping performance over original equipment shocks
• Monotube construction separates gas and oil for fade-resistant operation
• High-pressure nitrogen gas helps deliver immediate response
• Triple chrome plated piston rod helps reduce seal wear
• Designed for Super Duty Ford truck valving and component requirements
• Supports steering response and suspension control on heavier-duty setups
• Dust cover included

Detailed Description

KYB 554388 is a rear suspension shock absorber with a compressed length of 16.3 inches, an extended length of 26.5 inches, and a 10.20-inch stroke. It uses an E2(12X38) lower mount and an E1 upper mount. The monotube design keeps the hydraulic working area and gas charge separated, which helps maintain consistent damping under repeated use. This makes the shock a practical choice for Ford F-250 Super Duty and Ford F-350 Super Duty rear suspension service where load stability and road control matter.

This part cross-references Monroe Shocks & Struts 911265 for the same application.

What It Helps Address

• Excessive rear-end bounce after bumps or dips
• Reduced control when towing or carrying heavier loads
• Shock fade from repeated suspension cycling
• Loose steering feel caused by worn rear damping
• Ride instability on trucks with larger tires and wheels

Installation Notes and Fitment

Fits 2017-2019 Ford F-250 Super Duty, rear, Monotube Performance Upgrade; Except Off Road Suspension; Gas-a-just.

Fits 2011-2016 Ford F-250 Super Duty, rear, Monotube Performance Upgrade; w/o Off Road Suspension; Gas-a-just.

Fits 2008-2016 Ford F-350 Super Duty, rear, Monotube Performance Upgrade; w/ Single Rear Wheels; Gas-a-just.

Fits 2008-2010 Ford F-250 Super Duty, rear, Install a monotube shock absorber to enhance performance.; Gas-a-just.

Verify mount style, suspension configuration, and rear application before installation. This shock is for rear use only and is not listed for off-road suspension configurations shown in the fitment notes.

Quality Assurance

KYB designs Gas-a-just shocks with a monotube architecture that supports consistent damping and reduced aeration-related fade. The triple chrome plated piston rod is used to help reduce seal wear and maintain smooth operation over time.