KYB 555601 Shock Absorber - Rear

Rear OE-Style Shock for Ford, Lincoln, and Mercury

KYB Gas-a-just 555601 is a rear monotube shock absorber built as an OE-style replacement for select Ford Crown Victoria, Lincoln Town Car, and Mercury Grand Marquis applications. It is designed to restore original ride control while adding quicker response for vehicles that work, tow, or carry larger wheels and tires.

Key Features

• Monotube OEM replacement design for direct suspension service
• Separate gas and oil chambers for consistent damping and fast response
• High-pressure nitrogen gas helps maintain fade-free operation
• Triple chrome plated piston rod helps reduce seal wear and fluid leakage
• Rear fitment for 2003-2011 Ford Crown Victoria, 2003-2011 Lincoln Town Car, and 2003-2011 Mercury Grand Marquis
• Dust cover included
• Part number: 555601

Product Details

The KYB Gas-a-just line is a monotube shock absorber series focused on restoring factory handling characteristics with a firmer, more responsive feel when demand increases. For the Crown Victoria, Town Car, and Grand Marquis rear suspension, KYB 555601 uses a high-pressure monotube layout with an air-free hydraulic working area and a separate nitrogen gas chamber. That design supports steady control during normal driving and quicker damping response when the suspension is loaded or working harder. This part cross-references Monroe Shocks & Struts (e.g., 5993) for the same application.

What It Helps Address

• Excessive rear bounce or float over uneven pavement
• Reduced steering and body control from worn rear shocks
• Shock fade during towing or heavier-duty use
• Ride instability from aging OE suspension components
• Seal wear and fluid leakage associated with shock failure

Installation Notes

• Fits 2003-2011 Ford Crown Victoria, rear; except Police Car and Taxi; mount kit SM5267 required with 555601
• Fits 2003-2011 Lincoln Town Car, rear; mount kit SM5267 required with 555601
• Fits 2003-2011 Mercury Grand Marquis, rear; mount kit SM5267 required with 555601
• Verify rear suspension configuration before ordering
• KYB recommends new strut mounts, part number SM5267, to reduce noise and vibration

Quality Assurance

KYB designs the Gas-a-just line as an OE monotube replacement to help restore the vehicle manufacturer’s intended control and handling. The monotube construction and high-pressure gas charge are used to support consistent damping response in daily driving and load-bearing conditions.