KYB KG5556 Shock Absorber - Rear

KYB Gas-a-just Rear Shock for Full-Size Ford, Lincoln, and Mercury

The KYB Gas-a-just KG5556 is a rear monotube shock absorber built for drivers who want firmer control, quicker response, and consistent damping. It is engineered for full-size Ford, Lincoln, and Mercury applications, including Thunderbird, Cougar, Continental, and Mark VII fitments.

Gas-a-just Product Line

KYB Gas-a-just shocks use a monotube design with separate gas and oil chambers. That layout helps maintain response under load, reduces fade from aeration, and adds damping performance when the vehicle is carrying more weight, towing, or running larger tires and wheels.

Key Features

• Part number KG5556
• Rear suspension shock absorber
• Monotube design with air-free hydraulic response and high-pressure nitrogen gas support
• Up to 25% more damping performance than original equipment shocks
• Triple chrome plated piston rod helps reduce seal wear
• Dust cover included
• Designed for full-size Ford, Lincoln, and Mercury platforms
• Cross-reference: Monroe Shocks & Struts 5861

Detailed Description

KYB KG5556 is built for rear suspension applications where stable handling and controlled ride quality matter. The monotube construction separates the gas and oil, which helps the shock respond quickly and resist performance loss from aeration. The higher gas pressure also improves steering response and supports vehicles that work harder than stock, including those with towing loads or heavier wheel and tire setups. This part cross-references Monroe Shocks & Struts 5861 for the same application.

Compatible With 1980-1992 Ford Thunderbird, rear; 1980-1988 Mercury Cougar, rear; 1982-1987 Lincoln Continental, rear; and 1984-1992 Lincoln Mark VII, rear. It also fits 1981-1986 Mercury Cougar, rear, and 1981-1988 Ford Thunderbird, rear, for applications calling for a monotube rear shock such as the KYB Gas-a-just KG5556.

What It Helps Address

• Excessive rear-end bounce over bumps
• Reduced control during braking and cornering
• Shock fade from heat and aeration
• Loose ride feel on heavier full-size cars
• Delayed response on vehicles with upgraded tires and wheels

Installation Notes and Tips

Verify compressed length, extended length, and mount style before installation. KG5556 measures 14.02 inches compressed, 23.27 inches extended, and 9.25 inches of stroke, with an E2(12.8x38) lower mount and S1 upper mount. Confirm rear fitment against the vehicle’s suspension configuration, especially on models with electronic suspension conversion notes or PRC-related applications.

Quality Assurance

KYB designs Gas-a-just shocks for consistent damping performance and durable operation in demanding driving conditions. The monotube layout, high-pressure gas charge, and chrome piston rod construction are intended to support long-term suspension control on the specified Ford, Lincoln, and Mercury applications.