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Put 35s on a JK with factory gears and you feel it right away: the transmission hunts on the highway, the engine lives too low in its rev range, and fuel economy drops. Regearing both axles brings the effective ratio back where the factory set it. It is also the most commonly mis-ordered job on a JK, because the parts you need depend on whether it is a Rubicon and what ratio it left the factory with.
This guide covers the 2007-2018 JK only. The JL and JT use different axles and different gear sets.
Step One: Know Your Axles
| JK Model | Front Axle | Rear Axle | Common Factory Ratios |
|---|---|---|---|
| Sport, Sahara, most non-Rubicon | Dana 30, reverse rotation, 27 spline | Dana 44, 30 spline | 3.21, 3.73, some 4.10 |
| Rubicon | Dana 44, reverse rotation, factory locker | Dana 44, 32 spline, factory locker | 4.10 |
The ratio is on the axle tag and on the build sheet. Do not guess from the trim badge. Plenty of JKs have been swapped, and a used Jeep may have had gears changed already. Our guide on finding your axle ratio shows how to confirm it.
Step Two: Pick the Ratio for Your Tires
The goal is to get back near the factory feel. These are the ratios most JK builders land on:
| Tire Size | Typical Choice | Notes |
|---|---|---|
| 33 inch | 4.10 to 4.56 | A 3.21 or 3.73 Jeep gains the most here. 4.56 suits the 3.8L. |
| 35 inch | 4.88 | The most common JK regear. Good highway manners with the 3.6L. |
| 37 inch | 5.13 to 5.38 | 5.13 for mostly street, 5.38 for heavy builds and the 3.8L automatic. |
The 2007-2011 3.8L makes less torque than the 2012-2018 3.6L, so if you are between two ratios on a 3.8L, go one step lower (numerically higher). Heavy armor, a rooftop tent and a trailer all push the same way. For the math behind it, see our gear ratio after bigger tires guide.
Step Three: Do You Need New Carriers?
This is where most JK regear orders go wrong. Both JK axles have a carrier break, meaning the carrier that holds a low numerical ratio cannot hold a high numerical one.
- Dana 30 front: the break is between 3.54 and 3.73. A 3.21 Jeep needs a 3.73-and-up carrier, such as our JK Dana 30 standard carrier. A 3.73 or 4.10 front can keep its carrier.
- Dana 44 rear (non-Rubicon): the break is between 3.73 and 3.92. Both 3.21 and 3.73 Jeeps need a 3.92-and-up carrier to run 4.56 or deeper. A factory 4.10 Jeep is already on the right carrier.
- Rubicon: factory 4.10 means both locker carriers are already on the deep-gear side. Gears drop onto your existing lockers.
If you need a carrier anyway, it is the right moment to decide on traction. A selectable locker or a limited slip installed now costs no extra labor. See our carrier break and locker ordering guide.
Step Four: Gears and Install Kits
Every axle needs a ring and pinion set and a master install kit with new carrier and pinion bearings, shims, a pinion seal, a crush sleeve and ring gear bolts. Do not reuse old bearings on new gears.
| Part | Non-Rubicon | Rubicon |
|---|---|---|
| Front gears | Dana 30 reverse, 4.88 | Dana 44 reverse, 4.88 |
| Front install kit | Dana 30 master kit | Rubicon front master kit |
| Rear gears | Dana 44 rear, 4.56 | Rubicon-specific rear set |
| Rear install kit | Non-Rubicon rear master kit | Rubicon rear master kit |
If you would rather buy it all in one box, complete packages such as the JK stage 2 regear kit with diff covers or the non-Rubicon 5.13 gear package include gears and install kits for both axles. Many builders also add a crush sleeve eliminator so pinion preload can be reset later without a new sleeve.
What a JK Regear Typically Costs
- Gears and install kits, both axles: roughly $800 to $1,000 in parts.
- Carriers, if needed: about $200 to $400 each for open carriers, more for lockers.
- Labor: a good gear shop typically quotes 6 to 10 hours for both axles, often $1,000 to $1,800.
After the job, the JK computer has to be told the new axle ratio and tire size with a programmer. Skip this and the speedometer, shift points and stability control will all be off. Then follow a proper ring and pinion break-in before you tow or wheel hard.
Regear Your JK Once
JK Dana 30 and Dana 44 gear sets, master install kits, carriers and complete regear packages. Ships fast from the USA.
Shop Hard Parts →FAQ
Can I regear just the rear of my JK?
No. Front and rear ratios must match on a 4x4, or the transfer case and driveline will bind in four-wheel drive.
What gear ratio for 35s on a JK?
4.88 is the most common choice for a 3.6L JK on 35 inch tires. A heavy 3.8L build may want 5.13.
Do I need new carriers to regear a 3.73 JK?
On a non-Rubicon 3.73 JK, the Dana 30 front can keep its carrier, but the Dana 44 rear needs a 3.92-and-up carrier for 4.56 or deeper gears.
Can I reuse my Rubicon lockers?
Yes. Rubicon lockers are already on the deep-gear carrier, so new 4.56, 4.88 or 5.13 gears bolt to them.