Description
The FOX® 987-24-021 2.5 Performance Series Rear IFP HTO Shock is a bolt-on rear shock for 2017-2026 Ford F-250 and F-350 Super Duty 4WD trucks running a 4-6 inch rear lift, delivering 12.69 inches of travel through a 2.5-inch smooth body design.
IMPORTANT: This shock is valved specifically for a 4-6 inch rear lift on 2017-2026 F-250 and F-350 Super Duty trucks. It is sold individually. This part number is one of a family of rear-specific 2.5 Performance Series shocks for this truck generation — FOX® 987-24-003 covers a 2-3.5 inch rear lift and FOX® 987-24-023 covers a 6-8 inch rear lift. Confirm your rear lift height before ordering, as installing the wrong variant will result in incorrect ride height and damping performance.
FOX® 2.5 Performance Series HTO shocks are bolt-on units built with position-sensitive technology, vehicle-specific valving, and larger pistons to improve on- and off-road performance over stock shocks. The 2.5-inch shock body is impact-extruded from 6061-T6 aluminum and features Type II clear-anodized plating that efficiently dissipates heat and resists corrosion.
An internal floating piston (IFP) separates the shock oil from the high-pressure nitrogen charge inside the shock body, keeping damping performance consistent and preventing oil aeration under hard use. High-flow, velocity-sensitive damping is tuned specifically for this application.
Hydraulic Top Out (HTO) technology adds usable, position-sensitive rebound damping control both on and off the pavement. HTO reduces harsh top-outs and increases ride comfort by forcing shock oil through a secondary shim stack to slow shaft speed near full extension — particularly beneficial after installing heavier, aggressive tires or when lifted higher than OEM specification.
The shock uses a 5/8-inch hard chrome-plated shaft with eyelet mounts on both ends. FOX® backs this shock with a Limited Lifetime Warranty.
- Fits 2017-2026 Ford F-250 and F-350 Super Duty 4WD trucks running a 4-6 inch rear lift
- 2.5″ impact-extruded 6061-T6 aluminum shock body with Type II clear-anodized plating
- Internal Floating Piston (IFP) separates shock oil from nitrogen charge
- Hydraulic Top Out (HTO) piston for position-sensitive rebound control
- High-flow, velocity-sensitive, application-specific damping
- 5/8″ hard chrome-plated shaft
- No reservoir, no external compression adjuster — direct bolt-on installation
- FOX® Limited Lifetime Warranty
- Sold individually
| Part Number | 987-24-021 |
| Position | Rear |
| Series | Performance |
| Body Diameter | 2.5″ |
| Travel | 12.69″ |
| Extended Length | 33.88″ |
| Compressed Length | 21.29″ |
| Top Mount | Eyelet |
| Bottom Mount | Eyelet |
| Shaft | 5/8″ hard chrome-plated |
| Piston Technology | Internal Floating Piston (IFP), Hydraulic Top Out (HTO) |
| Body Material | Impact-extruded 6061-T6 aluminum, Type II clear-anodized |
| Warranty | Limited Lifetime |
| Quantity | Sold individually |
This shock is designed for 2017-2026 Ford F-250 and F-350 Super Duty 4WD trucks (F-350 King Ranch, Lariat, Limited, Platinum, XL, and XLT trims; F-350 Limited coverage begins with the 2018 model year) running a 4-6 inch rear lift as detailed above. This is a rear, lift-height-specific application — confirm your exact rear lift height before ordering, and do not substitute this part number for 987-24-003 (2-3.5 inch rear lift) or 987-24-023 (6-8 inch rear lift).