Yukon Gear & Install Kit Package For Jeep JK Non-Rubicon in a 4.88 Ratio

Yukon Gear Install Kit Package for Jeep JK Non-Rubicon, 4.88 Ratio (YGK013)

The YGK013 install kit package from Yukon Gear delivers a complete re-gear solution for the Dana 30 front and Dana 44 rear axles found in non-Rubicon Jeep Wrangler JK models, stepping up to a 4.88 gear ratio. YGK013 is the ideal choice for JK non-Rubicon owners who have moved to 35-inch tires and want aggressive, responsive power delivery both on and off the pavement. The 4.88 ratio provides more low-end torque multiplication than a 4.56 swap and is one of the most popular choices for JK owners who also plan to add larger tires in the future. This single kit includes ring and pinion sets plus all the installation hardware needed for a complete professional installation on both axles.

Features and Benefits

• Complete re-gear kit covering Dana 30 front and Dana 44 rear axles in one package
• 4.88 gear ratio ideal for 35-37 inch tire applications on non-Rubicon JK Wranglers
• Includes ring and pinion sets for both axles plus all install hardware (bearings, seals, shim packs, crush sleeves)
• Yukon Gear components machined to precise tolerances for correct backlash, quiet operation, and long service life
• Simplifies the re-gear project by supplying front and rear components together
• Important: If your JK originally has the 3.21 factory ratio, a new front carrier is required and sold separately
• For non-Rubicon JK only (Dana 30 front axle) - not compatible with Rubicon Dana 44 front
• Fits 2007-2018 Jeep Wrangler JK and Unlimited JK non-Rubicon

Vehicle Fitment

Specifications

What's Included

• Ring and pinion set for Dana 30 front axle (4.88 ratio)
• Ring and pinion set for Dana 44 rear axle (4.88 ratio)
• Front install kit (pinion bearing set, pinion seal, shim pack, crush sleeve)
• Rear install kit (pinion bearing set, pinion seal, shim pack, crush sleeve)
• Differential gaskets for front and rear

Frequently Asked Questions

What is YGK013?
YGK013 is a complete gear and install kit package for regearing the Dana 30 front and Dana 44 rear axles of a non-Rubicon Jeep Wrangler JK to a 4.88 ratio. It includes ring and pinion gear sets for both axles plus all necessary installation hardware.

How does 4.88 compare to 4.56 for a JK build?
A 4.88 ratio provides greater torque multiplication than a 4.56, which means stronger low-speed pulling power and better crawling ability. The trade-off is slightly higher engine RPM at highway speed. For JK owners planning to run 35-37 inch tires and use the vehicle frequently off-road, 4.88 is typically the preferred choice over 4.56.

Will YGK013 work in a Rubicon JK?
No. YGK013 is designed for non-Rubicon JK Wranglers with a Dana 30 front axle. Rubicon models use a Dana 44 front axle. For Rubicon-specific kits, see YGK015 (4.88) or YGK016 (5.13).

What if my JK originally had the 3.21 gear ratio?
If your JK was built with the 3.21 ratio, the factory front open carrier is not compatible with the 4.88 ring gear. A new front carrier must be sourced separately before YGK013 can be installed correctly.

Does installing YGK013 affect my vehicle warranty?
Under the Magnuson-Moss Warranty Act, an automaker or dealer cannot void a vehicle warranty simply because an aftermarket part was installed, unless they can prove the aftermarket part directly caused a failure. Consult your dealer for guidance on your specific warranty situation.

Do I need to re-gear both axles at the same time?
Yes, always re-gear both axles simultaneously. Running mismatched ratios between the front and rear axles causes severe drivetrain binding in 4WD and will damage the transfer case. YGK013 is intentionally sold as a front-and-rear kit to prevent this issue.

Is professional installation recommended?
Ring and pinion setup requires precise shimming for pinion depth and carrier bearing preload, plus backlash measurement with a dial indicator. While a skilled DIYer with appropriate tools can complete the job, professional installation by a drivetrain shop is strongly recommended to ensure proper gear mesh pattern and long-term durability.

What warranty comes with YGK013?
YGK013 is covered by Yukon Gear's limited warranty against defects in materials and workmanship. Contact Yukon Gear directly for warranty terms and claim procedures.

Installation Instructions

1. Drain both front and rear differential fluid. Remove differential covers and clean all mating surfaces.
2. Disconnect the front and rear driveshafts from the differentials.
3. Remove the carrier assemblies from both differential housings. Inspect all bearings; replace carrier bearings if worn.
4. If the vehicle originally had a 3.21 factory gear ratio, replace the front carrier with a compatible 4.88 carrier before installing the new ring gear.
5. Press the new 4.88 ring gears onto the carriers for both front and rear. Torque ring gear bolts to Yukon Gear specification.
6. Press new pinion bearing cups and cones onto the new pinion gears. Never reuse old pinion bearings.
7. Set pinion depth in each housing using the included shim pack and a dial indicator. Correct pinion depth is critical for proper gear engagement.
8. Install the pinion into each housing using the new crush sleeve. Set pinion bearing preload per the specification in the included instruction sheet.
9. Install the carrier assemblies and set ring and pinion backlash to 0.005-0.009 inch using a dial indicator, adjusting shims as needed.
10. Check gear contact pattern using gear marking compound; the pattern should be centered on the tooth face. Adjust shims if the pattern is too far toward the toe or heel.
11. Install new differential cover gaskets and reinstall the covers. Torque cover bolts to specification.
12. Reconnect driveshafts and fill both differentials with the correct gear oil. Road test and re-check for leaks.

Proposition 65 Warning: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.p65warnings.ca.gov.