Changing Axle Fluid 101

t1Changing axle fluid is easy and only costs about $20 compared to $50-$90 at the shop. It also is a great time to inspect your jeep to avoid a possible disaster down the road.

Cars/Trucks/Jeeps should have their axle fluid changed much more frequently if they are used in off-road or towing situations. If you have any thought you may have gotten water into your housing change your fluid immediately.

This writeup is written for a 98 Jeep TJ however it should apply to any vehicle. (Check your own manual for correct fluid types)

Tools and supplies needed

  • RTV sealentt2
  • Oil collector pan
  • 13mm sockets
  • Towels / newspaper
  • Brake cleaner

75w-90 gear oil is standard however 75W-120 or 80W-140 can be used if you are towing or have a locker. I recommend synthetic but if you change often than standard is fine.

  • Dana 30 1.2 Liters
  • Dana 35 1.65 Liters
  • Dana 44 1.9 Liters


  1. Place a oil collection pan under the diff with some newspaper or rags under it.
  2. Undo the fill plug
    Tip: Dana 30s and 44s the plug is metal and requires a 3/8 socket wrench with no socket. Dana35s have a rubber plug you pry off.
  3. Loosen up all the bolts with a 13mm socket (don’t remove them yet)
  4. Remove all bolts leaving just the top bolt in place. This allows you to empty the contents of the diff without the cover falling into the pan.t3
  5. Try to break the RTV seal by pushing the cover to one side or pulling it slightly away from the diff.
    Tip: Sometimes the use of a rubber mallet can be used or a block of wood and hammer.
  6. All the fluid will then drain into the oil pan. Yes it smells weird..
  7. Once the fluid drains remove the top bolt and set the cover aside.
  8. t4Take a can of brake cleaner and use a lint free towel to clean out the inside of the diff. Check for any pieces of metal on forgein objects. Inspect the inside of the diff or any cracked gears or anything that looks outta place.
  9. Clean the old RTV off the diff and diff cover. Do not using anything metal or abrasive. Clean with brake cleaner and let dryt6
  10. Put a bead of RTV gasket maker around the diff making sure to have a nice bead

  11. t7Put the cover on and loosely hand tighten all the nuts. Let the RTV dry for a few minutes (15 is good or start the other end)
  12. Torque all the bolts down to factory settings
  13. Fill the diff with gear oil.
    Tip: If you can’t tip the bottle up all the way just use a second bottle and keep filling the first bottle. A good idea is get a diff fluid pump but I don’t find them necessary and don’t use one even so i have one.
  14. Replace the fill plug and torque to specs. Dispose of the oil, correctly.
  15. Have a beer