KYB 551108 Suspension Strut - Rear

KYB Gas-a-just Rear Strut for Lexus GS

The KYB Gas-a-just 551108 is a rear suspension strut built as an OE-style monotube replacement for select Lexus GS applications. It is engineered to restore original handling response while adding the higher-pressure gas design needed for vehicles that carry extra load, tow, or run larger wheels and tires.

Gas-a-just Product Line

KYB Gas-a-just struts use two working chambers: an air-free hydraulic section for control and responsiveness, and a high-pressure nitrogen gas section with a floating piston for consistent ride quality and quick response. This design separates gas and oil to reduce fade and improve steering feel, making the KYB 551108 a direct-fit rear strut choice for Lexus GS350 and GS300 service work.

Key Features

• OE-style monotube replacement for the rear suspension
• Restores designed control and handling on Lexus GS applications
• High-pressure monotube construction separates gas and oil for fade-resistant operation
• Built for vehicles that work, tow, or use heavier tires and wheels
• Triple chrome plated piston rod helps reduce seal wear from fluid leakage
• Higher gas pressure supports quicker steering response
• Supports proper operation of electronic safety systems by maintaining suspension behavior
• Internal rebound spring included; dust cover not included

Detailed Description

Part number 551108 is a KYB Gas-a-just rear suspension strut for 2007-2011 Lexus GS350 and 2006 Lexus GS300 applications. It is a monotube design with a compressed length of 16.82 inches, an extended length of 21.51 inches, and a stroke length of 4.69 inches. Mounting details include a lower mount type E2(14.2X60) and an upper mount type 12X1.25. The Gas-a-just design is intended to restore the vehicle’s original suspension control while providing firmer response under demanding driving conditions. For Lexus GS owners looking for a rear strut replacement, KYB 551108 offers a direct OE-style solution that matches the platform’s suspension requirements.

What It Can Help Address

• Rear suspension noise or poor damping performance
• Excessive body motion over bumps and dips
• Reduced steering response from worn struts
• Handling changes caused by heavier wheels and tires
• Ride control loss from fluid leakage or internal wear

Installation Notes and Tips

Fits 2007-2011 Lexus GS350, rear, recommended OEM replacement; exc. Adaptive Control Suspension. Fits 2006 Lexus GS300, rear; replace the suspension strut and coil spring assembly according to the manufacturer’s instructions. Verify mount style and dimensions before installation, and inspect related suspension components such as springs, bushings, and hardware condition during service. This part cross-references Monroe Shocks & Struts (e.g., 172286, 182286) for the same application.

Quality Assurance

KYB is an OE supplier known for suspension components engineered to match factory ride and handling characteristics. The Gas-a-just line is built around a monotube architecture that supports consistent damping performance and responsive control in daily driving and load-bearing conditions.