KYB 551140 Shock Absorber - Rear

KYB Gas-a-just Rear Shock Absorber

The KYB Gas-a-just 551140 is a rear suspension shock absorber built for drivers who want firmer control than a standard twin-tube design. It is engineered for the 2010-2012 Hyundai Santa Fe and 2011-2013 Kia Sorento, with response characteristics suited to vehicles that carry loads, tow, or run larger wheels and tires.

Gas-a-just Performance Line

KYB Gas-a-just monotube shocks use separate hydraulic and high-pressure gas chambers to keep damping consistent and responsive. The design helps reduce fade from aeration, improves steering response, and supports electronic safety systems by maintaining suspension behavior closer to the vehicle maker’s intended operation. Part number 551140 is part of KYB’s Gas-a-just line for Asian SUVs.

Key Features

• Up to 25% more damping performance than original equipment shocks
• Monotube construction separates gas and oil for fade-free operation and quick response
• High gas pressure improves steering response and control
• Triple chrome plated piston rod helps reduce seal wear and fluid leakage
• Designed specifically for Asian SUVs
• Includes dust cover and internal rebound spring
• Rear application with compressed length 11.45 in., extended length 16.81 in., and stroke length 5.36 in.

Detailed Description

KYB 551140 is a rear shock absorber that uses a monotube layout with an air-free hydraulic working area and a separate nitrogen gas chamber. That construction gives the shock fast reaction to road inputs while maintaining consistent damping under repeated use. For the Hyundai Santa Fe and Kia Sorento, this rear shock is a direct choice for restoring controlled ride behavior on vehicles that see daily driving, towing, or added wheel and tire weight. This part cross-references Hyundai 553100W600 and Kia 553101U300 for the same application.

What It Helps Address

• Excessive rear bounce after bumps
• Reduced steering response from worn rear shocks
• Shock fade during repeated suspension movement
• Fluid leakage caused by seal wear
• Loss of control on vehicles carrying heavier loads or larger tires

Installation Notes and Tips

Fits 2010-2012 Hyundai Santa Fe, rear, and 2011-2013 Kia Sorento, rear. Verify lower mount type E2(16X38) and upper mount type E2(16.1X50) before installation. Check that the compressed and extended lengths match the original shock dimensions for the vehicle. Replace worn rear shocks in pairs on the same axle when service procedures call for matched damping.

Quality Assurance

KYB is a major OE supplier, and the Gas-a-just line is built with application-specific valving for Asian SUVs. Part number 551140 is engineered to maintain consistent damping performance and support the suspension behavior expected by the vehicle manufacturer.