KYB KG5420 Shock Absorber - Rear

Rear Shock for GM Heavy-Duty Applications

The KYB Gas-a-just KG5420 is a rear suspension shock absorber built for GM trucks and chassis applications that need firmer control than a standard twin-tube design. It uses a monotube layout with separate gas and oil chambers to deliver quick response, reduced fade, and more consistent damping under load.

Fits 1975-1999 Chevrolet P30, rear; Fits 1979-1999 GMC P3500, rear; Fits 1993-1996 Chevrolet G30, rear; Fits 1993-1996 GMC G3500, rear; Fits 1989-1991 Chevrolet R3500, rear; Fits 1987-1991 GMC R3500, rear; Fits 1982-1989 Chevrolet P20, rear; Fits 1982-1989 GMC P2500, rear; Fits 1987-1989 GMC R2500, rear; Fits 1987-1988 Chevrolet R20, rear; Fits 1987-1988 Chevrolet R30, rear; Fits 1975-1986 Chevrolet C20, rear; Fits 1975-1986 Chevrolet C30, rear; Fits 1979-1986 GMC C2500, rear; Fits 1979-1986 GMC C3500, rear; Fits 1975-1980 Chevrolet P10, rear; Fits 1979-1980 GMC P1500, rear.

• Up to 25% more damping performance than original equipment shocks
• Monotube design separates gas and oil for fade-resistant operation
• High-pressure nitrogen chamber adds immediate response when load or road conditions change
• Triple chrome plated piston rod helps reduce seal wear and fluid leakage
• Valving and components are tuned for GM truck and chassis applications
• Supports steering response and suspension control on vehicles with heavier tires and wheels

Gas-a-just Line Details

KYB Gas-a-just shocks are designed for drivers who want more control from the suspension without giving up normal ride comfort. The KG5420 uses an air-free hydraulic working area for responsiveness and a separate high-pressure gas chamber with a floating piston, allowing the shock to react quickly as road conditions change. This makes the KYB Gas-a-just KG5420 a strong rear shock choice for Chevrolet P30 and GMC P3500 chassis, as well as other GM C, G, P, and R-series rear applications listed above.

Common Uses

• Rear-end bounce or excessive body movement on GM trucks and chassis vehicles
• Reduced damping control when carrying cargo or towing
• Shock fade from repeated suspension movement and heat buildup
• Loose steering feel caused by worn rear suspension damping
• Uneven ride control on vehicles with larger, heavier tires and wheels

Installation Notes

Verify compressed length, extended length, and mount style before installation: compressed length 14.33 in., extended length 23.19 in., stroke length 8.86 in. The KG5420 uses E2 lower and upper mounts, includes a dust cover, and does not use an internal rebound spring, B-stop, or R-stop. On Mor/Ryde-equipped Chevrolet P30 and GMC P3500 motorhome chassis, confirm the Mor/Ryde service part number before ordering. This part cross-references Monroe Shocks & Struts (e.g., 34960) for the same application.

Quality Assurance

KYB designs Gas-a-just monotube shocks with separate gas and oil chambers to maintain consistent damping and reduce fade. The KG5420 is built to support the suspension performance expected on GM truck and chassis platforms, including vehicles where braking, steering, and electronic safety systems depend on suspension behavior staying within manufacturer specifications.