KYB 553381 Suspension Shock Absorber - Rear

KYB Gas-a-Just Rear Shock for Mercedes-Benz

The KYB Gas-a-Just 553381 is a rear suspension shock absorber built as an OE-style monotube replacement for select Mercedes-Benz C-Class and E-Class models. It is designed to restore original ride control, steering response, and suspension behavior on vehicles with standard suspension setups.

Gas-a-Just shocks use a two-chamber monotube design with an air-free hydraulic working area and a high-pressure nitrogen gas chamber. That layout supports consistent damping, quick response, and stable control during normal driving and under heavier load conditions.

Key Features

• Monotube OE replacement for rear suspension applications
• Compressed length: 15.83 in.; extended length: 22.83 in.; stroke length: 7.00 in.
• Lower mount type: E2 (10.2 x 48); upper mount type: S1
• High-pressure gas and oil separation for fade-resistant operation
• Triple chrome plated piston rod to reduce seal wear and fluid leakage risk
• Responsive damping for improved steering feel and suspension control
• Supports vehicles used for towing, heavier tires, and higher load demands
• R-stop included; dust cover, internal rebound spring, and B-stop not included

Detailed Description

KYB Gas-a-Just 553381 is engineered for rear suspension service on Mercedes-Benz C300, C350, C250, E350, E400, E450, E63 AMG, and C63 AMG applications listed below. It is a direct-fit shock absorber for standard suspension vehicles and is commonly selected when replacing worn OE monotube shocks on the Mercedes-Benz C-Class and E-Class platform. This part number, 553381, is also referenced by OE and aftermarket cross numbers for the same application.

The Gas-a-Just line is built around a monotube design that separates gas and oil to maintain consistent damping response. KYB uses this layout to help restore the handling balance the vehicle was designed to have, while the higher gas pressure improves response when the suspension is working harder. This makes the KYB Gas-a-Just 553381 a practical choice for rear shock replacement on Mercedes-Benz models that need controlled ride quality without adaptive or air suspension components.

This part cross-references Monroe Shocks & Struts 39047 for the same application.

What It Helps Address

• Excessive rear-end bounce or oscillation
• Reduced steering response from worn rear shocks
• Fluid leakage from aging shock absorbers
• Loss of control over bumps, dips, and uneven pavement
• Ride instability on higher-load or larger-wheel setups

Installation Notes and Fitment

Compatible with rear suspension applications only. Fits 2022-2023 Mercedes-Benz E450, rear, w/ Standard Suspension, w/o Air and w/o Adaptive Control Suspension; Gas-a-just. Fits 2022 Mercedes-Benz C300, rear, w/ Standard Suspension and w/o Air Suspension; Gas-a-just. Fits 2016-2021 Mercedes-Benz C300, rear, Recommended OEM Replacement; w/ Standard Suspension and w/o Air Suspension; Gas-a-just. Fits 2019-2021 Mercedes-Benz E450, rear, Recommended OEM Replacement; w/ Standard Suspension, w/o Air and w/o Adaptive Control Suspension; Gas-a-just. Fits 2018 Mercedes-Benz E400, rear, Recommended OEM Replacement; w/ Standard Suspension, w/o Air and w/o Adaptive Control Suspension; Gas-a-just. Fits 2015-2017 Mercedes-Benz E400, rear, Replace suspension strut and coil spring assembly according to manufacturer's instructions.; Gas-a-just. Fits 2008-2015 Mercedes-Benz C350, rear, Recommended OEM Replacement; (Exc. Electronic Suspension); Gas-a-just. Fits 2012-2014 Mercedes-Benz C250, rear, Recommended OEM Replacement; w/o Performance Suspension; Gas-a-just. Fits 2008-2014 Mercedes-Benz C300, rear, Recommended OEM Replacement; (Exc. Electronic Suspension); Gas-a-just. Fits 2011-2014 Mercedes-Benz E350, rear, Recommended OEM Replacement; (Exc. Appearance Package); Gas-a-just. Fits 2010-2014 Mercedes-Benz E350, rear, Recommended OEM Replacement; (Exc. Stability Control and Appearance Package); Gas-a-just. Fits 2012 Mercedes-Benz C63 AMG, rear, Recommended OEM Replacement; w/o Air Suspension; Gas-a-just. Fits 2010 Mercedes-Benz E350, rear, Recommended OEM Replacement; w/ Sport Suspension; Gas-a-just. Fits 2010 Mercedes-Benz E63 AMG, rear, Recommended OEM Replacement; w/ Sport Suspension (Except Air Ride and Electronic Suspension); Gas-a-just.

Verify suspension type, package exclusions, and mounting dimensions before installation. This shock absorber is intended for vehicles listed in the fitment data and should be matched to the rear position only.

Quality Assurance

KYB designs the Gas-a-just line as an OE monotube replacement to help restore factory-style control and handling characteristics. The monotube construction, high-pressure gas chamber, and chrome-plated piston rod are used to support consistent damping performance and reduce seal wear over time.