Axle Swapping Your Jeep : From Junkyard to Crate Builds

When upgrading your Jeep for serious off-road use, your axles are one of the most critical components. Bigger tires mean more torque, more leverage, and more stress on the drivetrain — and once you move past stock sizes, the right axle swap becomes essential.

Tire Size vs. Minimum Recommended Axle

• 33" Tires – Stock Dana 44s (Rubicon models) with chromoly shafts hold up well. Dana 30 fronts are at their limit and can work for mild trails.

• 35" Tires – Dana 44s are the baseline; upgrade shafts, gears, and lockers for reliability.

• 37" Tires – Heavy-duty Dana 44s or upgraded crate axles like a Dynatrac ProRock 44/60 hybrid. Stock Rubicon 44s survive with caution, but they’re stressed so upgraded internals are highly recommended for reliability.

• 40" Tires – Solid one-ton territory. Supersty Dana 60/Sterling 10.5 combos or Dana 60 front with 14-bolt rear are common. Crate options like Dynatrac ProRock 60 or ECGS 60 are built for this range.

• 42" Tires and bigger – Hardcore builds demand 14 bolt and Dana 80 rears, heavy-duty Dana 60 or 14-bolt fronts, massive steering upgrades, and big brakes.

Popular Axle Swap Options

OEM / Junkyard Swaps

1. Dana 44

   • Pros: Lighter than one-tons, good for 35–37" tires with upgrades, affordable.

   • Cons: Limited for heavy rock crawling with big tires.

2. Dana 60 (Kingpin, Super Duty, or aftermarket)

   • Pros: Extreme strength, handles 37–43" tires, huge aftermarket support.

   • Cons: Heavier, sometimes lower clearance unless high-pinion. Bigger tires can help offset less ground clearance.

3. GM 14-Bolt Rear

   • Pros: Cheap, bombproof full float axle shafts, great for 40"+ tires, easy to shave for clearance. Third pinion bearing for added support and less gear deflection.

   • Cons: Heavy, low clearance in stock form.

4. Ford 9"

   • Pros: Excellent ground clearance, strong center section, easy gear swaps.

   • Cons: Needs upgrades for 40"+ tires.

Aftermarket Crate Axles

1. Dynatrac (ProRock 44, ProRock 60, ProRock 80)

   • Pros: Built new with premium components, high-pinion designs for clearance, ready-to-bolt-in for most Jeeps, supports massive tires with minimal modding.

   • Cons: Price — but you’re paying for a turnkey, warranty-backed axle.

2. East Coast Gear Supply (ECGS)

   • Pros: Custom-built axles tailored to your Jeep’s specs, choice of gear ratios and lockers, can use new or remanufactured housings. Readily available replacement parts if needed. Fully customizable to fit your exact needs. 

   • Cons: Lead times can vary depending on build complexity.

3. Currie Enterprises (RockJock series)

   • Pros: Excellent for Jeeps running 35–40" tires, great ground clearance, race-proven designs.

   • Cons: Replacement parts availability is limited and dealing directly with the manufacturer is a must. 

Bottom Line:
For smaller 33–35" builds, upgraded factory axles or lighter-duty crate options work well. For 37"+ tires, you’re better off moving into Dana 60 territory — whether that’s a junkyard Super Duty swap or a premium Dynatrac ProRock 60 that bolts right in. For 40–43" tires, one-tons or bigger are the only way to keep your rig from becoming a trail-side repair project.