Fox 2.5 Performance Series IFP HTO Rear Shock | Single | 0-1.5" Lift | 2017-2025 Ford F-250/F-350 Super Duty | SKU 987-24-001
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Before ordering, verify your vehicle details, current setup, and SKU with OFAS fitment support so your upgrade matches your build.
Shipping & Delivery
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Fitment, Shipping & Product Support
The Fox 2.5 Performance Series IFP HTO Rear Shock (SKU 987-24-001) is a step-up heavy-duty rear shock for the 2017–2025 Ford F-250 and F-350 Super Duty, running stock height to 1.5" of rear lift. The larger 2.5" Type II anodized aluminum body increases oil volume for superior heat dissipation and corrosion resistance versus the standard 2.0" Fox shock. Internal Floating Piston (IFP) separates shock oil from high-pressure nitrogen for optimized, consistent damping. Hydraulic Top Out (HTO) technology uses a secondary shim stack to provide position-sensitive rebound damping control, reducing harsh top-outs — particularly beneficial after installing heavier, more aggressive tires or on applications lifted higher than OEM spec. Vehicle-specific valving and larger pistons. Hardware included — washers, bushings, and nuts. 1-year Fox limited warranty. Sold as a single rear shock.
Component Specifications
| Spec | Detail |
|---|---|
| SKU / Part Number | 987-24-001 |
| Brand | Fox |
| Series | 2.5 Performance Series |
| Position | Rear |
| Quantity | Single shock — order 2 for a complete rear pair |
| Body | 2.5" Type II anodized aluminum |
| Damping | IFP (Internal Floating Piston) + HTO (Hydraulic Top Out) |
| HTO Function | Secondary shim stack provides position-sensitive rebound damping, reduces harsh top-outs |
| Lift Range | 0–1.5" rear lift |
| Hardware Included | Washers, bushings, nuts |
| Warranty | 1-year Fox limited warranty |
| Application | Towing, hauling, heavier/aggressive tire setups, sustained heavy-duty use |
| Sold As | Each |
What Is and Is NOT Included
| Item | Included |
|---|---|
| 1x rear shock | ✓ |
| Washers, bushings, nuts | ✓ |
| Second rear shock | ✗ NOT included — order quantity 2 for a pair |
| Front shocks | ✗ NOT included — sold separately (e.g., 987-24-000 for matching front) |
Fox 2.5 HTO Super Duty Family — Confirm Your Platform Generation
| SKU | Years | Position | Lift Range |
|---|---|---|---|
| 987-24-054 | 2005–2016 | Rear | 0–1.5" |
| 987-24-001 (this listing) | 2017–2025 | Rear | 0–1.5" |
| 987-24-003 | 2017–2025 | Rear | 2–3.5" |
| 987-24-023 | 2017–2026 | Rear | 6–8" |
These are not interchangeable across the 2017 generation break or across lift ranges — confirm your exact model year and lift height before ordering.
Verified Fitment
| Vehicle | Years | Lift Range | Status |
|---|---|---|---|
| Ford F-250 Super Duty | 2017–2025 | 0–1.5" | ✓ |
| Ford F-350 Super Duty | 2017–2025 | 0–1.5" | ✓ |
| Ford F-250/F-350 Super Duty | 2005–2016 | Any | ✗ Different chassis generation — order 987-24-054 instead |
| Ford F-450/F-550 | Any | Any | ✗ Different rear suspension geometry |
| Ford F-150 | Any | Any | ✗ Different platform |
| Rear lift exceeding 1.5" | — | — | ✗ Requires a different HTO part number — e.g., 987-24-003 for 2-3.5" |
Critical Compatibility
| Configuration | Notes |
|---|---|
| 2005–2016 Super Duty | Does not fit — order Fox 987-24-054 for the pre-redesign chassis |
| Rear lift exceeding 1.5" | Requires a different Fox 2.5 HTO part number |
| Long-travel or coilover conversion suspension | Not compatible |
| Mismatched left/right shocks | Replace in pairs for handling balance |
Common Questions
What does HTO actually do?
HTO stands for Hydraulic Top Out. A secondary shim stack inside the shock provides position-sensitive rebound damping control, slowing the shock shaft as it nears full extension. This reduces harsh top-out feel — especially noticeable after installing heavier tires or on a lifted truck.
Does this fit my 2015 F-350?
No. This part number is for the 2017+ redesigned Super Duty chassis. A 2005–2016 truck needs the corresponding pre-redesign part number (987-24-054).
What's the real difference between this and the standard Fox 2.0?
The larger 2.5" body holds more oil and nitrogen, improving heat dissipation under sustained heavy use. The HTO technology adds position-sensitive top-out control the standard 2.0 doesn't have. This is the step-up choice for trucks that tow or haul frequently, or run heavier/more aggressive tire setups.
Do I need one or two?
This listing is for a single shock. Order quantity 2 for a complete rear pair, and replace both sides together for balanced handling.
The Obsidian Take
The 987-24-001 is for the 2017–2025 F-250/F-350 Super Duty owner who tows or hauls frequently, or runs heavier/more aggressive tires, and wants the larger 2.5" body and Hydraulic Top Out control over the standard Fox 2.0 shock.
The check that matters most: confirm your truck is 2017 or newer. The pre-2017 generation requires a different Fox HTO part number entirely.
Non-Returnable Notice: Once installed, this unit is non-returnable. Confirm model year and rear lift height before ordering.
⚠️ California Proposition 65 Warning: This product may expose you to chemicals known to the State of California to cause cancer or reproductive harm. For more information visit P65Warnings.ca.gov.
Specifications sourced from Fox and authorized distributor documentation. Obsidian Forged Auto Supply is an authorized Fox dealer. Manufacturer specifications are subject to change without notice.