KYB 553388 Shock Absorber - Rear

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

The KYB Gas-a-just 553388 is a monotube rear shock absorber built as an OE-style replacement for select Mercedes-Benz applications. It is engineered to restore original ride control, steering response, and suspension stability on vehicles such as the Mercedes-Benz E250, E350, E400, E550, and E63 AMG.

KYB’s Gas-a-just line uses a high-pressure monotube design with separate gas and oil chambers for consistent damping and quick response during normal driving and load changes.

Key Features

• OE monotube replacement for rear suspension service
• High-pressure monotube construction separates gas and oil for fade-resistant operation
• Air-free hydraulic piston and valve area for responsive control
• High-pressure nitrogen gas chamber adds immediate damping response
• Triple chrome plated piston rod helps reduce seal wear from fluid leakage
• Designed for vehicles that tow, carry heavier loads, or use larger wheels and tires
• Supports proper suspension behavior for electronic safety systems
• Compressed length: 15.15 in; extended length: 22.63 in; stroke length: 7.48 in
• Lower mount type: E2(10.2x48); upper mount type: S1

Detailed Description

KYB Gas-a-just shock absorber 553388 is built to replace the original rear monotube shock on select Mercedes-Benz models while maintaining the vehicle’s intended handling balance. The monotube design keeps the gas and oil separated, which supports consistent damping response and helps the shock react quickly when road conditions change. This makes it a practical choice for drivers who want restored control on a Mercedes-Benz E350 rear suspension, a Mercedes-Benz E250 rear shock replacement, or a Mercedes-Benz E550 rear suspension service.

The Gas-a-just platform is suited to applications that see added demand from towing, heavier wheels and tires, or frequent load changes. Its high gas pressure improves steering response and helps the suspension stay composed. Part number 553388 is also referenced for Mercedes-Benz OE numbers 2123200630 and 2123201030.

This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

What It Helps Address

• Excessive rear-end bounce or oscillation
• Reduced damping control after shock wear
• Delayed response during braking, cornering, or lane changes
• Ride instability from heavier wheels, tires, or load changes
• Suspension behavior that no longer matches factory handling

Installation Notes and Tips

• Fits 2014-2016 Mercedes-Benz E250, rear, recommended OEM replacement; exc. Sport Suspension; Gas-a-just
• Fits 2010-2016 Mercedes-Benz E350, rear, recommended OEM replacement; without sport suspension; Gas-a-just
• Fits 2014-2015 Mercedes-Benz E400, rear, replace suspension strut and coil spring assembly according to manufacturer’s instructions; Gas-a-just
• Fits 2012-2014 Mercedes-Benz E550, rear, recommended OEM replacement; w/o Air and Sport Suspension; Gas-a-just
• Fits 2010 Mercedes-Benz E63 AMG, rear, recommended OEM replacement; w/o Sport, Air Ride and Electronic Suspensions; Gas-a-just

Verify rear suspension configuration before ordering, especially on vehicles with sport, air, or electronic suspension systems. Follow manufacturer service procedures during replacement to maintain correct ride height and suspension geometry.

Quality Assurance

KYB is a long-established OE supplier, and the Gas-a-just line is built to OE-style specifications for direct-fit suspension service. The monotube design, high-pressure gas charge, and chrome piston rod construction are used to support consistent damping performance and long service life in demanding driving conditions.