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> Jeep Articles > Technical & Installation - Engine / Drivetrain > Jeep 101 - Differential Fluid (oil) Change

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Technical / Installation Articles - Engine / Drivetrain

Jeep 101 - Differential Fluid (oil) Change

Article written by Moab Man

Date Added: 11/28/2010

Maybe you?re too lazy, just forget, or don?t know how; but your Jeeps' axles need a little love from time to time.

As I sit here watching the snow fall, penning this article, it occurred to me that this is a great time for getting some maintenance done during what is for most of us the wheeling ?off season.? What better place to start that at the bottom; let?s take a quick look at our axles.

No other mechanical component is in the dirt, mud, and water more than our axles. And while they do have seals, they are water resistant - not water proof. The upside? Axles are not as touchy as something like an automatic transmission, but contaminants can cause long term damage none the less.

Follow along as we change the axle oil in our Jeep TJ. Ideally, put your Jeep on jack-stands, but this can be done on the ground if you?re lifted.



1. Remove the bolts from your differential cover. Leave the top center bolt threaded in two or three threads.

 You can remove the fill plug from the differential cover prior to starting, or once the cover is removed. Metal fill plugs are easier to do prior to removing the differential cover. Rubber plugs are easier with the cover off.
  If the plug is metal (D30 & D44), and has a square hole, use a 3/8? ratchet to unscrew and remove it. Clean any metal from the fill plug magnet. Rubber plugs (D35 & 8.25) pop out, but sometimes put up quite a fight depending on the temperature of the rubber.

2. Using a rubber mallet, hit the differential cover (sideways blow) until it breaks loose and the oil spills out.
 We are assuming you know to properly collect and dispose of this gear oil as you would any motor oil. If you don't know, most chain automotive parts stores will take the used oil off your hands.

3. Remove the top bolt and differential cover.

4. Inspect the teeth on your ring gear, works best if the Jeep is on jack-stands and you can rotate the axles.
 Good idea to use your finger and swab out the bottom of the axle housing. Some axles have a small pocket at the bottom where any chips or chunks may settle.

5. Strip/scrape the old RTV from the differential cover and axle housing.

6. With the old RTV removed and the mating surfaces cleaned of any oil, apply RTV to both mating surfaces.
 We like blue RTV, but black also works.

7. Bolt the differential cover back in place. Tighten the bolts in a crossing pattern and torque to specification.

8. Fill the differential until oil leaks out of the fill hole.
 Limited slip axles may require a limited slip additive ? check owners manual.

9. Replace the plug.

10. Specifications
  • D35 & D44 Front / rear factory covers: 30 ft lbs.
  • Factory fill plug bolt: 25 ft lbs.
  • D35 Oil weight: 75w90 (difficult to find) 80W90 often substituted
  • D44 Oil Weight: 75w90 and 75W140 (check owners manual)

Installation Issues

If in the course of performing this maintenance you find metal chunks, there are greater issues at hand. Our recommendation? Seek the assistance of a professional. You will likely need a rebuild. After a diagnosis, carefully consider your options. For a bit more money than a basic rebuild, it may be a good time to do that axle upgrade you have always wanted or maybe step up to some higher quality internals.

Final Thoughts

This information to change your differential oil is the same for most any axle. However, ALWAYS confirm torque, oil weight, and additive (if required) with your owners manual.

Watch our YouTube video to see this maintenance performed.

Purchase / Vendor Info

Vendor Name: Purchased locally.

Our Thank You's!

Thank you for reading MOABJEEPER Magazine.

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