Monroe 66458 Gas-Magnum 60 Series Heavy-Duty Shock Absorber

The Monroe Gas-Magnum 60 Series Shock Absorber (MPN: 66458) is a premium, nitrogen gas-charged suspension component engineered for Class 3–6 commercial vehicles. Designed to meet or exceed demanding OEM manufacturer specifications, this heavy-duty shock delivers firm, controlled damping without sacrificing ride comfort — even under high-mileage and severe-duty operating conditions.

Featuring a 1-3/8-inch bore and 10-stage full-displacement valving tuned to handle road extremes, the Monroe 66458 provides consistent, precise damping control. The larger bore and 2-inch reserve tube hold significantly more fluid than standard 1-inch bore shocks, improving efficiency and maintaining performance over time. All-weather fluid with special additives resists breakdown in extreme temperatures, ensuring consistent ride quality year-round.

Key Features:

• Nitrogen gas-charged for quicker response, reduced aeration, and minimized shock fade
• 10-stage full-displacement valving adjusts to road extremes for exceptional handling and a smooth, consistent ride
• 1-3/8-inch bore with 2-inch reserve tube for up to twice the fluid capacity of standard shocks
• Nitrocarburized piston rod with sintered iron piston for reduced friction and extended service life
• Shouldered and bonded bushings with sleeve prevent bushing walkout for improved quality and durability
• Arc welds up to 360° for maximum structural durability
• Multi-lip fluid seal prevents leaks and protects internal components
• Dust shield included to guard against contaminants
• All-weather fluid with special additives resists oil breakdown in extreme temperatures
• Extended length: 20.74 in. | Collapsed length: 13.89 in. | Stroke: 6.85 in.
• Upper & lower loop bushing and sleeve mounts (20MM sleeve inner diameter)
• Sold individually

Replacing worn shocks with the Monroe 66458 helps reduce excessive vibration, improving tire life, minimizing downtime, and lowering cost-per-mile — a smart investment for fleet and commercial operators. Backed by Monroe's 90-Day Risk-Free Ride Offer and Limited Commercial Warranty.

Cross-references: Gabriel 83396, Gabriel 89396, FOX Commercial Truck Shocks 98031020.