Mojave-specific Fox 2.5 internal bypass shock service
The Mojave's Fox 2.5-inch internal bypass shocks are the most sophisticated suspension hardware on any factory Jeep. They need professional service every 30,000–50,000 miles or after any serious abuse. Don't skip this — a neglected bypass shock loses its calibration well before it shows visible damage.
Standard shocks control damping through a single piston with calibrated valving. The Fox 2.5 Internal Bypass shock runs additional bypass tubes alongside the main shock body. As the shock compresses through its travel, the bypass tubes progressively restrict flow — the shock becomes firmer as it approaches full compression. This gives the Mojave an extremely supple ride at small suspension inputs (highway, light trail) while providing firm resistance at the end of travel (preventing bottoming on high-speed terrain).
This calibration is engineered specifically for the Mojave. The bypass positions (where the bypass tubes open and close) are set for the Mojave's ride height, travel, and the specific desert-running use case. A standard Fox 2.5 reservoir shock — even from the same diameter family — is not the same product.
Fox's general recommendation for performance shocks in trail use: inspect every 10,000–15,000 miles, service every 30,000–50,000 miles. For a Mojave used in actual desert running — Sonoran desert, Baja-style terrain, high-speed washboard — shorten that to 20,000–30,000 miles.
Signs your shocks need service before the mileage interval:
- Reduced damping feel — the truck feels "floaty" over terrain it used to manage firmly
- Oil residue or weeping around the shock body or reservoir
- Unusual noise (clunking, cavitation) from the shock during compression
- Loss of the distinct firmness-at-end-of-travel characteristic
Fox recommends their factory-certified service centers for internal bypass shocks. The bypass tube positioning requires specialized knowledge — it's not a generic shock rebuild. Incorrect reassembly changes the shock's calibration profile, which defeats the point of having bypass shocks.
Locate a Fox-certified service center via their website before shipping or bringing the shocks in. Some high-end off-road shops have bypass rebuild experience and appropriate equipment. Ask specifically if they've serviced Fox internal bypass shocks, not Fox reservoir shocks — they're different processes.
What the service includes: Disassembly, inspection of seals, piston, bypass tubes, and body; cleaning; replacement of seals and oil; nitrogen recharge to spec; recalibration of bypass positions; reassembly and testing.
The Mojave's shocks are calibrated for speed and compliance over large undulations — desert washes, high-speed dirt roads, Baja-style terrain. The valving and bypass positions favor this use case.
This calibration is not ideal for slow-speed rock crawling. At low speed, the bypass tubes are mostly open, which means the shock is relatively underdamped for technical rock terrain. The Mojave is genuinely better in the desert than on a technical rock trail — that's by design.
If you primarily run rocks and bought a Mojave, that's workable — it's not undriveable on rocks — but understand that the suspension is optimized for a different environment.
DIY: Removing and reinstalling the shocks is within reach for someone comfortable with suspension work. It requires removing the wheels, unbolting the shock ends, and dealing with the coilover spring if applicable. The spring compressor is mandatory.
Send out: The rebuild itself is shop work for most people. Sending the shocks to Fox or a certified rebuilder and reinstalling the rebuilt units is the practical approach for anyone who doesn't have bypass-specific rebuild experience.
Getting the shocks off the truck is DIY-doable; the rebuild is the shop's job. Working one corner at a time:
- Loosen the wheel lug nuts, lift the corner, support the frame on a stand, and remove the wheel.
- Support the axle with a floor jack to take spring tension off the shock. On the coilover front, the spring is captive on the shock body — do not unbolt anything until the axle is supported.
- Remove the lower shock bolt (19mm), then the upper mount hardware. The reservoir is mounted remotely on a bracket — unclip the reservoir before pulling the shock free.
- Bag and label each shock by corner. Fox needs to know corner position and your truck's loaded weight to recalibrate correctly.
- Reinstall in reverse, and torque the lower bolt with the suspension at ride height, not hanging — torquing at full droop preloads the bushings wrong.
If you're comparing this to a full replacement instead of a rebuild, the JT shock upgrade and expedition lift guides cover aftermarket options.
| Path | What you get | Cost |
|---|---|---|
| Fox rebuild, you R&R | Factory calibration restored, 4 shocks | $480–600 + your labor |
| Shop R&R + rebuild | Turnkey, no tools needed | $900–1,300 |
| Replace with aftermarket 2.5 | New long-travel or reservoir shocks | $1,600–3,500 |
The rebuild is the value play if you want to keep the Mojave's engineered desert calibration. Aftermarket replacement makes sense only if you are changing the truck's mission — for example, moving toward a mid-travel lift setup tuned for mixed use rather than pure desert running.
Steps
- Inspect shocks at each oil change — look for weeping and check damping feel
- At 30,000 miles or when performance drops, schedule service
- Locate a Fox-certified service center or qualified bypass shock rebuilder
- Remove shocks from the vehicle (this is DIY-doable; see your vehicle-specific removal procedure)
- Ship or bring shocks to the service center with your weight/application info
- Reinstall rebuilt shocks; torque to spec with truck at ride height
Why it works
- The Fox 2.5 internal bypass is genuinely superior suspension hardware for desert running
- Proper service restores calibration — the shock performs like new after a rebuild
- Fox's service center network is well-established
Trade-offs
- Service cost per shock is significant — plan $400–$600 for a full set rebuild
- Finding a qualified local rebuilder may require shipping the shocks out
- The desert calibration is a real limitation for technical rock use
Tools required
- floor jack
- jack stands
- breaker bar
- 19mm socket
- shock spring compressor (if coilover)
- nitrogen fill equipment or shop access
Parts
| Part | Vendor | Est. price |
|---|---|---|
| Fox 2.5 internal bypass shock rebuild service (per shock) | Fox Racing Shox | ~$120 |
| Fox shock oil (FLOAT fluid, for bypass shock use) | Fox Racing Shox | ~$28 |
| Nitrogen fill service (at a qualified shop) | local suspension shop | ~$40 |
Sources
Related
- Shock Absorber Upgrade — Jeep Gladiator JT
- Expedition Lift for the Gladiator — Long-Arm System ($2,000+)
- All Jeep Gladiator JT guides & tools
- Browse the full DIY database
Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.