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🧾 Overview
The FOX 2.5 HTO Performance Series Rear Shock (AX4001) is engineered as a direct replacement for 1999–2026 Ford Super Duty F250 and F350 trucks running stock rear height up to a 1" rear block or rear airbag setup. Designed for heavy-duty use, this shock delivers improved control, stability, and comfort without compromising daily drivability.
Featuring FOX’s Hydraulic Top Out (HTO) technology, this shock provides position-sensitive rebound damping that reduces harsh top-out events and improves ride quality—especially beneficial for trucks running heavier tires or mild rear suspension upgrades. Built with a 2.5” aluminum body and high-flow damping piston, it’s engineered for serious performance on and off the road.
✔ Designed for stock to 1" rear lift
✔ Hydraulic Top Out (HTO) technology
✔ Ideal for trucks with rear airbags or mild leveling
✔ Sold individually
🛠 Installation
- Direct bolt-on replacement for factory rear shock.
- No cutting or fabrication required.
- Basic hand tools required.
📌 Specs
- Key Features & Benefits
- Hydraulic Top Out (HTO) Piston Technology
- High-Flow Velocity-Sensitive Damping
- Internal Floating Piston (IFP)
- 2.5” Impact Extruded 6061-T6 Aluminum Body
- Type II Clear Anodized Finish
- 5/8” Hard Chrome Shaft
- 📘 Specifications
- Collapsed Length: 18.79"
- Extended Length: 29.58"
- Shock Body: 2.5” 6061-T6 Aluminum
- Technology: Hydraulic Top Out (HTO)
- Application: Rear
- Sold As: Single
- 📦 What’s Included (What’s in the Box)
- (1) FOX 2.5 HTO Rear Shock – AX4001
- FOX Part Number: 987-24-001
- 🛡 Warranty
- Covered under The Axiom No-Nonsense Lifetime Warranty.
- Warrantied for life to the original purchaser against manufacturer defects, premature wear, or breakage.
- Push it to the limit—we don’t care. If the part lets you down, it will be made right.
⚠️ Fitment Notes
- 1999–2026 Ford F250 Super Duty
- 1999–2026 Ford F350 Super Duty
- ⚠️ Fitment Notes
- Rear shock application
- Fits stock rear height up to 1" rear block or airbag kit
- Compatible with factory and most leveling kits
- Sold as a single shock – order quantity of 2 required per vehicle