Revolution Gear & Axle 07-18 Jeep Wrangler JK Rubicon Dana 44 Front 4.88 Ratio Ring &...

If you are regearing a 2007-2018 Jeep Wrangler JK Rubicon for 35 or 37 inch tires, the front axle needs gears too, and it is not the same set as the rear. The Revolution Gear & Axle D44RS-488RUB is a new 4.88 ring and pinion for the Rubicon's front Dana 44, which is a reverse rotation (high pinion) axle. It pairs with a 4.88 rear set so both axles turn at the same speed in four-wheel drive. Revolution lists the set with an 8.5 in. ring gear, a 24-spline pinion and 10 ring gear bolt holes drilled for both 7/16 in. and 1/2 in. bolts, cut from 8620 steel.

What the front ring and pinion does in a JK Rubicon Dana 44

In the front axle the pinion sits above the axle centerline and drives the ring gear on its coast side, which is why a front set is cut in reverse rotation and a standard rear set will not work here. The Rubicon left the factory with 4.10 gears in both axles. Moving to 4.88 deepens the ratio by about 19 percent, which brings engine speed on 35s and 37s back toward where it was on the stock tires, gives the automatic a usable top gear again and adds crawl control with the transfer case in low range. The front set also has to survive steering lock and rock loads, so a correct pattern and preload matter even more than in the rear.

Symptoms that point to new front gears

• Speedometer off and constant downshifting after a jump to 35 or 37 inch tires
• Binding, tire hop or a crow-hop feel in 4WD after only the rear axle was regeared
• A whine from the front of the Jeep that rises and falls with throttle, even in 2WD, because the front ring gear and driveshaft still turn with the wheels
• Metal paste on the fill plug or broken and chipped teeth after a hard hit with the locker engaged

How to confirm before you order

First confirm it is a Rubicon front Dana 44 and not the Dana 30 used on Sport and Sahara models; the axle tag and the factory front locker switch are the quickest clues, and our Dana 30 vs Dana 44 front axle guide shows the rest. Read the ratio off the tag. Front hub bearings on the JK are a common source of a similar hum, so jack up each corner and check for play and roughness before blaming gears. The JK regear kit buyer's guide covers which ratio suits each tire size and which carriers carry over.

Fitment

Revolution builds this set for the front Dana 44 reverse rotation axle of the 2007-2018 Jeep Wrangler JK Rubicon and Wrangler Unlimited Rubicon. It does not fit the Dana 30 front of non-Rubicon JKs, the rear Dana 44, a TJ Rubicon front or the 2018-up JL. Revolution lists the 3.73 version of this family as a 3.73-and-down carrier; deeper ratios, 4.88 included, belong to the same carrier series as the factory 4.10 Rubicon gears, so the stock locker carrier normally carries over. If the axle has been swapped or you are not sure what is under the Jeep, send us the year and VIN. Matching rear gears are here: the Yukon JK rear Dana 44 4.88 set, and the rest of the axle line is under hard parts.

Install notes

• Never reuse old bearings with new gears. The JK Rubicon front master install kit or the USA Standard JK Rubicon front overhaul kit supplies the bearings, races, shims and seal.
• Unplug the front locker connector and the axle disconnect wiring before pulling the carrier, and tag the shims as they come out.
• Revolution's D44JK chart row: 0.042 in. starting pinion depth, 22-35 in-lb new pinion bearing preload, 0.006-0.010 in. backlash, ring gear bolts 75 ft-lb (7/16 in.) or 135 ft-lb (1/2 in.), bearing caps 80 ft-lb. Read the pattern with marking compound on both sides of the teeth.
• Regear the rear at the same time with 4.88s; a 4.10 rear with a 4.88 front will bind the driveline the moment you shift into 4WD.
• Fill with the 75W-90 or 75W-140 gear oil your owner's manual lists for the front axle, follow the ring and pinion break-in procedure, change the oil at about 500 miles and reprogram the tire size and axle ratio.

Does this fit a JK Sport or Sahara front axle?

No. Non-Rubicon JKs use a Dana 30 front with a smaller ring gear. This set is only for the Rubicon front Dana 44. Sport and Sahara owners need a 4.88 Dana 30 reverse set.

Can I keep my factory Rubicon front locker carrier?

Normally yes. The factory Rubicon gears are 4.10, and 4.88 is in the same carrier series. Inspect the carrier bearings and locker first, and use the bolt size the carrier is tapped for.

Do I have to regear the rear at the same time?

Yes. Both axles must have the same ratio or the driveline binds in four-wheel drive. Order a 4.88 JK rear Dana 44 set with this front set.

Is 4.88 right for 35 inch tires on a JK Rubicon?

4.88 is the most common choice for 35s on a JK, especially with the 3.6L. Heavy builds on 37s often go to 5.13 or 5.38 instead.

What gear oil does the front axle take?

Use the weight listed in your owner's manual for the front axle, typically 75W-90 or 75W-140 GL-5. Change it after the first 500 miles to clear break-in wear metal.