FOX 987-24-054 Perf Series 2.5 IFP HTO Rear Shock 05-16 F-250/350 4WD 0-1.5" Lif

Vehicle Fitment

• 2005-2016 Ford F-250 Super Duty (4WD; all cab configurations - Regular Cab, SuperCab, Crew Cab; all bed lengths) - Confirmed fitment; rear shock
• 2005-2016 Ford F-350 Super Duty (4WD; all cab configurations; all bed lengths) - Confirmed fitment; rear shock
• Designed for vehicles at stock ride height through 1.5" of rear lift - confirm your specific rear lift height is within 0-1.5" before ordering. FOX offers additional 987-series variants for greater lift ranges on these platforms.
• 4WD models only - not confirmed for 2WD Super Duty rear applications.

Application Notes

• This is a single shock - one unit per order. The F-250/F-350 rear requires two shocks for a complete replacement. Order two units for a full rear pair.
• The 987-24-054 is a rear shock. FOX offers companion front shocks in the 987-series for the 2005-2016 F-250/F-350 platform; see the 987-24-002 (front, 2-3.5" lift) and related front variants for complete front/rear shock upgrades.
• Lift range: 0-1.5". This shock is engineered and valved for the suspension geometry of a 2005-2016 F-250/F-350 at stock height through 1.5" of rear lift. Installing this shock outside its specified lift range will result in suboptimal damping performance and may affect ride quality, handling, and shock service life.
• Installation is a direct bolt-on replacement - no drilling, cutting, or modification to the vehicle is required. Standard hand tools and a jack are needed for installation.
• The HTO (Hydraulic Top Out) feature is particularly beneficial on vehicles with heavier aftermarket tire and wheel packages or vehicles that have been lifted, as these conditions increase the frequency and severity of suspension top-out events that HTO is designed to manage.

Features

• 2.5" Impact Extruded 6061-T6 Aluminum Body - the 987-series 2.5" body is larger than FOX's 985-series 2.0" body, providing greater oil volume for improved heat dissipation under sustained off-road use, and greater damping force capacity for the heavier duty demands of the F-250 and F-350 platform. The impact-extruded aluminum body dissipates heat significantly faster than steel-bodied shock alternatives. Type II clear-anodized body plating provides superior corrosion and rust resistance.
• Internal Floating Piston (IFP) - the IFP separates the shock oil from the high-pressure nitrogen gas charge inside the shock body. This prevents the oil and nitrogen from mixing under agitation (aeration), which would cause inconsistent, foamy damping. The IFP maintains the nitrogen charge at consistent pressure against the oil column, ensuring stable, predictable damping performance across the full range of suspension travel and operating temperatures.
• Hydraulic Top Out (HTO) - when the shock reaches the end of its extension travel (top-out), the HTO piston forces oil through a secondary shim stack that provides progressive hydraulic resistance to slow the shaft's extension speed. This converts what would be a harsh mechanical top-out impact (shaft bottoming against the bump stop at the top of travel) into a controlled, progressive deceleration - reducing the jolt transmitted to the chassis, cab, and cargo. HTO is position-sensitive: it activates only in the final portion of extension travel and does not affect damping during normal operating stroke. The benefit is most pronounced on lifted trucks, trucks running heavier tires, and off-road applications where aggressive terrain causes the suspension to frequently cycle to full extension.
• High-Flow Velocity-Sensitive Damping - the damping piston is designed for high-flow fluid movement through the valving shim stacks, providing a wide range of force output across the full velocity spectrum of suspension inputs. Low-velocity inputs (slow-speed off-road undulation, parking lot dips) produce appropriate soft damping; high-velocity impacts (potholes, sharp road irregularities, off-road hits) produce proportionally higher damping force to control the shock shaft.
• Vehicle-Specific Valving - each FOX Performance Series shock is valved specifically for the application's weight, suspension geometry, spring rates, and intended use case. The 987-24-054 is tuned for the rear suspension loads, spring rates, and lift geometry specific to the 2005-2016 F-250/F-350 Super Duty 4WD at 0-1.5" of rear lift - not a generic valving that is adapted to the application.
• 5/8" Hard Chrome Shaft - the shaft's larger-than-standard diameter provides greater resistance to bending and deflection loads from lateral forces common in heavy-duty truck use, and the hard chrome surface provides wear resistance at the shaft seal interface.
• Position-Sensitive Technology - the 987-series Performance Series HTO shock provides position-sensitive damping behavior across its travel, with the HTO circuit activating in the top-out zone and the main valving calibrated for performance across the normal operating range.
• Bolt-On Direct Fit - installs to the factory shock mounting points on the 2005-2016 F-250/F-350 Super Duty rear suspension without modification.

Specifications

• Part Number: 987-24-054
• Series: FOX Performance Series 2.5
• Type: Smooth Body IFP HTO Shock
• Position: Rear
• Vehicle Fitment: 2005-2016 Ford F-250/F-350 Super Duty 4WD
• Lift Range: 0-1.5"
• Body Diameter: 2.5"
• Body Material: 6061-T6 impact-extruded aluminum, Type II clear-anodized
• Shaft: 5/8" hard chrome
• Reservoir Type: Internal Floating Piston (IFP) - no external reservoir
• Gas Charge: High-pressure nitrogen (separated from oil by IFP)
• HTO (Hydraulic Top Out): Yes
• Valving: High-flow velocity-sensitive; vehicle/application-specific
• Installation: Bolt-on, no modification required
• Quantity: 1 shock per order
• Warranty: 1-year limited warranty
• Made in USA: Yes (FOX, Watsonville, CA)

Included Components

• 1x FOX 987-24-054 Performance Series 2.5 Smooth Body IFP HTO Rear Shock

Product Description

The FOX 987-24-054 is the Performance Series 2.5 Smooth Body IFP HTO rear shock for the 2005-2016 Ford F-250 and F-350 Super Duty 4WD, valved and dimensioned for vehicles at stock height through 1.5" of rear lift. It replaces or upgrades the factory rear shock with a 2.5" impact-extruded 6061-T6 aluminum body - a meaningful step up in body diameter from the 2.0" body of FOX's 985-series Performance shocks - providing more oil volume for heat dissipation and more damping force capacity appropriate for the F-250 and F-350's heavier duty suspension loads, spring rates, and GVWRs.

The shock's defining feature over a standard IFP shock is the Hydraulic Top Out (HTO) system. On the 2005-2016 Super Duty platform - and especially on lifted examples running larger tires - hard acceleration over rough terrain or repeated off-road cycling frequently drives the rear suspension to full extension. Without HTO, this results in a mechanical impact as the shock shaft reaches the limit of its travel. With HTO, the shock's oil is forced through a secondary shim stack as the shaft approaches full extension, progressively decelerating the shaft through controlled hydraulic resistance rather than a hard mechanical stop. The feel in the cab is a significant reduction in the harshness of suspension top-out events - particularly noticeable on rutted trails, washboard surfaces, and aggressive off-road terrain where the rear suspension cycles frequently and forcefully. The IFP separates the oil from the nitrogen charge to prevent aeration and foam formation, maintaining consistent damping across extended use and temperature variation.

Vehicle-specific valving is calibrated for the 987-24-054's specific application - the rear suspension geometry, spring rates, and target ride behavior of the 2005-2016 F-250/F-350 4WD at 0-1.5" rear lift - rather than a generic curve adapted from another application. Installation is a direct bolt-on to the factory rear shock mounting hardware. One shock per order; two required for a complete rear set. FOX backs the 987-24-054 with a 1-year limited warranty.