FOX 987-24-023 Performance Series 2.5 IFP HTO Rear Shock F-250/350 4WD 6-8inLift

Vehicle Fitment

• 2017-2025 Ford F-250 Super Duty (4WD; all cab configurations - Regular Cab, SuperCab, Crew Cab; all bed lengths) - Confirmed fitment; rear shock
• 2017-2025 Ford F-350 Super Duty (4WD; all cab configurations; all bed lengths) - Confirmed fitment; rear shock
• Designed for vehicles with 6-8" of rear lift - confirm your specific rear lift height is within this range before ordering. FOX offers companion 987-series rear variants for other lift ranges on this platform. Match the correct lift range to your build for optimal damping geometry and performance.
• 4WD models only.
• 2017+ year range only - the rear shock mounting geometry, spring rates, and suspension travel of the 13th-generation Super Duty (2017+) differ from the prior generation. For 2005-2016 F-250/F-350 rear shock replacements at different lift ranges, see the 987-24-054 (0-1.5" lift, 2005-2016 rear). There is no FOX 987-series rear shock covering the 2005-2016 platform at 6-8" of lift under this part number.

Application Notes

• The 987-24-023 is the direct companion rear shock to the 987-24-022 front shock, completing the 6-8" lift range shock package for 2017-2025 F-250/F-350 Super Duty 4WD builds. For a complete front and rear shock upgrade at this lift range on the 2017-2025 platform, both the 987-24-022 (front) and 987-24-023 (rear) are required.
• The 2017+ F-250/F-350 rear suspension uses a leaf spring arrangement with solid rear axle. At 6-8" of rear lift - achieved through add-a-leaf packs, replacement multi-leaf springs, block lifts, or a combination - the rear shock mounting geometry and travel change significantly from stock. The 987-24-023 is valved specifically for the rear suspension behavior of this generation at this lift height, accounting for the altered shock angle, effective spring rate, and motion ratios present at 6-8".
• HTO (Hydraulic Top Out) is particularly relevant at 6-8" of rear lift on the Super Duty. Increased rear suspension travel at extreme lift heights means the shock reaches full extension more frequently and with greater velocity during off-road use - whether during rear axle droop on trail or upon landing from a water crossing or rough terrain event. HTO's progressive hydraulic resistance in the final extension travel converts these events from abrupt mechanical top-outs into controlled decelerations, protecting axle hardware, leaf spring U-bolts, and the shock's own end stops.
• At 6-8" of rear lift, extended brake lines, driveshaft modifications, and potentially a track bar or panhard bar relocation may be required in addition to replacement shocks. Verify all complementary suspension components for your specific lift configuration before installation.
• This is a single shock - one unit per order. Two are required for a complete rear axle replacement.
• Installation is a direct bolt-on replacement for the factory rear shock absorber - no drilling or modification to shock mounting points is required for the shock itself.

Features

• 2.5" body diameter - the 987-series 2.5" body provides more oil volume than a 2.0" body shock, delivering greater heat capacity and more consistent damping under the sustained loading that a heavily lifted, work-use Super Duty rear suspension imposes on shock absorbers. The F-250/F-350 rear axle regularly carries significant payload and towing loads in addition to off-road use - the 2.5" body's oil capacity handles these sustained, high-load conditions more effectively than a smaller-body shock.
• 6061-T6 aluminum body with Type II anodize - aluminum dissipates heat more efficiently than steel-bodied shocks and resists corrosion in the harsh underbody environment of a work truck operating in varying weather and road conditions.
• Internal Floating Piston (IFP) - separates shock oil from the high-pressure nitrogen gas charge to prevent aeration under aggressive or sustained cycling. At 6-8" of lift, the altered rear suspension geometry and increased travel increase the frequency and intensity of shock cycling compared to stock - the IFP ensures damping remains consistent and fade-free across these conditions.
• Hydraulic Top Out (HTO) - at the end of the shock's extension travel, the HTO piston directs oil through a secondary shim stack that provides progressive hydraulic resistance, decelerating the shaft before it contacts mechanical travel limits. On the heavily lifted F-250/F-350 rear suspension, increased droop travel makes top-out events more frequent and more forceful - HTO reduces the harshness transmitted to the chassis, leaf springs, and axle hardware, improving both ride quality and component longevity.
• Vehicle and lift-specific valving - the 987-24-023 is valved for the 2017-2025 F-250/F-350 rear suspension spring rates, axle weight, and geometry at 6-8" of lift, not adapted from a generic or lesser-lift tune. Valving is calibrated for both the loaded and unloaded conditions the Super Duty rear axle encounters in real-world use.
• 5/8" hard chrome shaft - provides bending resistance under the lateral loads generated by the altered geometry of a heavily lifted solid rear axle, with hard chrome surface treatment for wear resistance at the seal interface.
• Bolt-on direct fit - installs to the factory rear shock mounting hardware on the 2017-2025 F-250/F-350 without modification to the shock absorber mounting points.

Specifications

• Part Number: 987-24-023
• Series: FOX Performance Series 2.5
• Type: Smooth Body IFP HTO Shock
• Position: Rear
• Vehicle Fitment: 2017-2025 Ford F-250/F-350 Super Duty 4WD
• Lift Range: 6-8"
• Body Diameter: 2.5"
• Body Material: 6061-T6 aluminum, Type II anodized
• Shaft: 5/8" hard chrome
• Reservoir Type: Internal Floating Piston (IFP) - smooth body, no external reservoir
• HTO (Hydraulic Top Out): Yes
• Valving: Vehicle/lift-specific; position-sensitive
• Installation: Bolt-on direct fit
• Quantity: 1 shock per order
• Warranty: 1-year limited warranty

Included Components

• 1x FOX 987-24-023 Performance Series 2.5 Smooth Body IFP HTO Rear Shock

Product Description

The FOX 987-24-023 is the Performance Series 2.5 Smooth Body IFP HTO rear shock for the 2017-2025 Ford F-250 and F-350 Super Duty 4WD at 6-8" of rear lift - the direct companion to the 987-24-022 front shock, completing the full-vehicle 6-8" lift shock package for this generation of Super Duty. The 2017+ year range reflects the 13th-generation Super Duty's redesigned rear suspension architecture, which uses different mounting geometry, spring travel, and load characteristics than the 2005-2016 platform and requires its own lift-range-specific valving.

The rear suspension of a 6-8" lifted F-250/F-350 operates under conditions substantially different from a stock or moderately lifted truck: increased droop travel, altered shock angles, changed motion ratios relative to the leaf spring pack, and the continued presence of heavy payload and towing loads that define how a Super Duty rear suspension actually gets used. The 987-24-023's 2.5" body provides the oil volume necessary to absorb sustained heat under these conditions without fade - more oil means a higher thermal ceiling before damping force begins to degrade. The IFP keeps oil and nitrogen separate to maintain consistent damping through repeated cycling, and the HTO circuit progressively resists extension at travel limits rather than allowing abrupt mechanical top-outs that stress leaf spring hardware and axle components.

For the complete front and rear 6-8" lift shock package on the 2017-2025 F-250/F-350, the 987-24-022 (front) and 987-24-023 (rear) are ordered together. The 987-24-023 is sold as a single unit - two are required for a full rear axle replacement. At 6-8" of lift, extended brake lines, driveshaft considerations, and other lift-specific hardware should be confirmed before installation. FOX backs the 987-24-023 with a 1-year limited warranty.