Jeep JK Differential Fluid Change

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Jeep JK Differential Fluid ChangeChanging the fluid in your Jeep JK front and rear differentials is an important part of routine maintenance. Fresh gear oil insures your differentials are well lubricated and function properly. And, unlike previous Jeep Wranglers, it is not necessary to remove the differential cover in order to do this. It is however recommended that you do so anyway from time to time (possibly every other fluid change) as it will give you a chance to inspect your gears and catch any damage or unusual wear.

Following “Schedule B” in the Jeep owner’s manual (heavy driving), you should change your differential fluids every 15,000 miles. However it is always a good idea to do this IF you’ve submerged your axles in deep water for prolonged periods of time. This post will provide instructions on how to perform a Jeep JK differential fluid change that applies to either Dana 30 or Dana 44 axles.

Front Dana 44 differential needs 2.7 pints (1.35 quarts) and the rear needs 4.75 pints (2.375 quarts). If you have factory covers, all you need to do is fill up your differentials until gear oil oozes out of the fill hole. If you have an after market differential cover that has a higher fill hole than factory, DO NOT be tempted to add any more gear oil than is needed. Doing so will result in a differential that is over-filled and will cause gear oil to get pumped out of the breather tube, creating a stinky mess. Gear oil level only needs to reach the bottom of your axle tubes.

NOTE: Rear differentials with Trac-Lok (limited slip clutch type differential, not used on the Rubicon), require the limited slip additive for the clutch plates. You can also use synthetic gear oil as it will have friction modifier in it.
Jeep JK Rubicon requires regular gear oil. The Rubicon uses Tru-Lok which is a mechanical lock to lock the left and right axles together. Tru-Lok does not have clutch plates, so an additive is not required. In the Rubicon with Tru-Lok differentials, when the rear differential is not locked, the vehicle uses the TCS (Traction Control System) to monitor the amount of wheel spin of each of the driven wheels. If wheel spin is detected, brake pressure is applied to the slipping wheel(s) to provide stability. This feature of the TCS system functions similar to a limited slip differential and controls the wheel spin across a driven axle. If one wheel on a driven axle is spinning faster than the other, the system will apply the brake of the spinning wheel. This will allow more engine torque to be applied to the wheel that is not spinning. This is how the Rubicon gets by without a limited slip rear differential.

As with any other fluids, refer to your Jeep owner’s manual for the recommended gear oil viscosity. I own a 2012 JK Rubicon, with both front and rear Dana 44 axles, and the recommended gear oil is 80W-90.

Differential Fluid Capacity:
Jeep JK Rubicon front Dana 44     2.70 pints (1.35 quarts)
Jeep JK Rubicon rear Dana 44      4.75 pints (2.375 quarts)
Non Rubicon front differential        2.10 pints (1.05 quarts)
Non Rubicon rear differential         3.80 pints (1.90 quarts)

 

Disclaimer: Like I always mention I am not a professional mechanic, I just try to do as much work on my Jeep as possible. It helps me learn more about my vehicle and save some money that can be spent on parts and upgrades.
I take no responsibility for any injury or breakage which might occur if you decide to follow these steps. You have to decide if you’re comfortable working on your Jeep. If you’re not, please have a professional complete this project for you.

 

Parts and tools needed:

1. 4 Quarts of 80W90 Gear Oil (use synthetic IF you have a limited slip differential)

2. 3/8″ Drive Ratchet

3. 3″ Ratchet Extension

4. Oil drain pan

5. 3/8 hex bit (optional)

6. Brake Cleaner (optional)

7. Funnel (optional)

8. Rubber Gloves

9. Paper Towels

 

Procedure:

Step 1:

Prepare your tools and get everything ready before you start the project. Park your Jeep on a level surface, apply your emergency brake and put your transmission in park or in gear if you have a 6-speed manual transmission. Chock the wheels.

 

Step 2:

Ensure you have proper clearance and room to be able to insert the new gear oil bottle into the fill hole and tilt it upwards. If necessary, you can jack up the frame of your Jeep and rest it on jack stands, to lift the track bar and drag link higher, above the differential.

Jeep JK Differential Fluid Change

 

Step 3:

Locate both the fill bolt and the drain bolt on your differential. Remove fill bolt BEFORE removing the drain bolt. That way you can avoid a situation where you drain all the gear oil and then find out you have no way to fill the differential with fresh fluid.

Jeep JK Differential Fluid Change

 

Step 4:

Using the square head of a 3/8″ Drive ratchet, remove the fill bolt from your differential cover.
Some covers like Riddler use a fill bolt that requires use of a 3/8 hex bit to remove.

Jeep JK Differential Fluid Change

 

Step 5:

With the fill bolt removed, you can proceed to draining the old gear oil.

Jeep JK Differential Fluid Change

 

Step 6:

Place an oil drain pan underneath your differential. Then, using a 3/8″ drive ratchet with a 3″ extension attached to it, remove the drain bolt from the base of it as shown.

Jeep JK Differential Fluid Change

 

Step 7:

Allow your differential fluid to drain completely before proceeding.

Jeep JK Differential Fluid Change

 

Step 8:

Your Jeep’s drain bolt is magnetic and the inside end of it will most likely be fuzzy with fine iron filings. Use a paper towel and some brake cleaner to wipe the bolt clean. If you find any metal chunks, you should consider removing the differential cover in order to inspect the gears (if you do remove the cover you will need either RTV Silicone Gasket Maker or Lube Locker Differential Cover Gasket when reinstalling everything back together).

Using a 3/8″ drive ratchet with a 3″ extension attached to it, reinstall your drain bolt back on to the base of your differential. Tighten this bolt to 25 ft. lbs. of torque.

Jeep JK Differential Fluid Change

 

Step 9:

With the drain bolt installed and tightened, proceed to refill your differential with fresh gear oil. Pour in exactly the recommended amount of gear oil. If you still have stock differential cover, you can stop once fluid is oozing out of the fill hole.

Using the square head of a 3/8″ Drive ratchet, re-install fill bolt on to the differential cover. Use a 3/8″ hex bit if necessary. Tighten the bolt to 25 ft. lbs. of torque.

Jeep JK Differential Fluid Change

 

Step 10:

Follow the same steps with the rear differential.
Ensure you have proper clearance and room to be able to insert the new gear oil bottle into the fill hole and tilt it upwards. If necessary, you can jack up the frame of your Jeep and rest it on jack stands, to lift the track bar higher, above the differential.

Jeep JK Differential Fluid Change

 

Step 11:

Locate both the fill bolt and the drain bolt on your differential. Remove fill bolt BEFORE removing the drain bolt. That way you can avoid a situation where you drain all the gear oil and then find out you have no way to fill the differential with fresh fluid.

Jeep JK Differential Fluid Change

 

Step 12:

Using the square head of a 3/8″ Drive ratchet, remove the fill bolt from your differential cover.
Some covers like Riddler use a fill bolt that requires use of a 3/8 hex bit to remove.

Jeep JK Differential Fluid Change

 

Step 13:

Place an oil drain pan underneath your differential. Then, using a 3/8″ drive ratchet with a 3″ extension attached to it, remove the drain bolt from the base of differential. Allow the old fluid to drain completely before proceeding.

Use a paper towel and some brake cleaner to wipe the drain bolt clean. If you find any metal chunks, you should consider removing the differential cover in order to inspect the gears.

Using a 3/8″ drive ratchet with a 3″ extension attached to it, reinstall your drain bolt back on to the base of your differential. Tighten this bolt to 25 ft. lbs. of torque.

Jeep JK Differential Fluid Change

 

Step 14:

With the drain bolt installed and tightened, proceed to refill your differential with fresh gear oil. Pour in exactly the recommended amount of gear oil. If you still have stock differential cover, you can stop once fluid is oozing out of the fill hole.

Using the square head of a 3/8″ Drive ratchet, re-install fill bolt on to the differential cover. Use a 3/8″ hex bit if necessary. Tighten the bolt to 25 ft. lbs. of torque.

Jeep JK Differential Fluid Change

 

Step 15:

Pour the old gear oil into secure containers (use a funnel if necessary) and clean up any mess. Take your Jeep for a test drive to a local auto parts store where you can dispose of used oil safely and free of charge.

 

 

If you have any questions or suggestions, feel free to comment below.

 

 

April 14, 2019 |

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