FOX 2.5 PERFORMANCE SERIES IFP HTO SHOCK ABSORBER 987-24-009 | 2011-2026 6.6L Duramax (Rear - Lifted 0"-1")

Improve on-road control and off-road suspension performance in your Chevy Silverado or GMC Sierra 2500HD/3500HD with the FOX 2.5 Performance Series IFP HTO Shock Absorber. Featuring application-specific valving, a large 2.5-inch aluminum shock body, and position-sensitive damping technology, this shock is engineered for demanding heavy-duty truck applications.

The 2.5-inch impact-extruded 6061-T6 aluminum body provides increased oil capacity while efficiently dissipating heat during demanding use. A Type II clear-anodized finish helps protect the shock body against corrosion for long-term durability.

An Internal Floating Piston (IFP) separates the shock oil from the high-pressure nitrogen charge, helping prevent oil aeration and maintain consistent damping performance. FOX combines this design with vehicle-specific precision valving and high-flow, velocity-sensitive damping for controlled suspension response across varying terrain and driving conditions.

FOX Hydraulic Top Out (HTO) technology adds position-sensitive rebound control as the suspension approaches full extension. The system routes shock oil through a secondary shim stack to progressively slow shaft speed, helping reduce harsh top-out events and improve suspension control. This can be particularly beneficial on trucks equipped with heavier tires or suspension systems providing additional lift over stock.

The Performance Series shock is also fully rebuildable and re-tunable, allowing it to be serviced or adjusted as vehicle requirements change.

Features

• 2.5-inch shock body – Increased oil capacity supports consistent performance and improved heat management
• Hydraulic Top Out (HTO) – Provides position-sensitive rebound damping to help reduce harsh suspension top-outs
• Internal Floating Piston (IFP) – Separates shock oil from the high-pressure nitrogen charge to help prevent aeration
• Application-specific tuning – Factory valving is engineered for the intended vehicle application
• High-flow velocity-sensitive damping – Provides controlled response across changing suspension speeds
• 6061-T6 aluminum construction – Impact-extruded aluminum body provides strength and efficient heat dissipation
• Type II clear-anodized finish – Helps protect the aluminum body against corrosion
• 5/8-inch hard chrome shaft – Designed for strength and durability in demanding applications
• Fully rebuildable and re-tunable – Can be serviced and adjusted for changing suspension requirements
• Sold individually – One shock absorber per package

Specifications

• Series: FOX 2.5 Performance Series
• Extended Length: 26.02"
• Compressed Length: 17.34"
• Travel: 8.68"
• Top Mount: Eyelet
• Bottom Mount: Eyelet
• Shaft Diameter: 5/8"
• Shock Body Diameter: 2.5"
• Body Material: 6061-T6 Aluminum
• Quantity: 1

Application Notes

• Manufacturer lift-height recommendations are intended as a general application guide.
• Due to variations between aftermarket suspension systems, measuring the vehicle's required extended and compressed shock lengths is recommended to verify proper fitment.
• Shock absorbers are sold individually.

Application: Chevy Silverado / GMC Sierra 2500HD & 3500HD

Part Number: 987-24-009