How to Change Your Transfer Case Fluid in Your Jeep JL – Easy Preventive Maintenance That Gets Overlooked
It is very important to keep your vehicle running with regularly scheduled maintenance. Not doing this can cause components in your vehicle to wear out and break down faster than normal, or completely fail.
Pretty much everyone knows to change their engine oil, and some know that it is a good idea to change the axle differential oil after water crossings or every 40k miles. But how many people know to change their transfer case fluid?
According to the JL manual under Section 8 servicing and maintenance, the transfer case fluid should be checked every 30k miles and changed every 60k miles. Now if you do a lot of off-roading, it might be a good idea to change this every 30k miles instead of the 60k. If you drive the 6-speed manual transmission, it requires you to change fluid every 30k miles. It would be a good idea to do the transfer case at the same time since both use the same fluid and everything is out, keeping them both on a 30k cycle. This is an easy job to do, so let me show you how to get it done!
Tools & Materials
- 2 quarts of Mopar ATF+4 Automatic Transmission Fluid (or any ATF+4 that meets or exceeds FCA & Chrysler standards)
- A Quart Fluid Pump
- High-Temperature Thread Sealant
- Oil Catch Pan or Bucket
- Brake Cleaner
- Shop rags or shop towels
- 10mm Hex Bit Socket
- Metric Sockets
- Torque Wrench
- Safety Glasses
- Latex Mechanic Gloves
Step 1. Remove Transfer Case Skid Plate
For easier access to the transfer case, fill and drain holes; it is recommended to remove the transfer case skid plate. It can be left on, but the draining of the fluid can be very messy if not removed. The transfer case skid plate is only held on by 4 bolts and 2 nuts. Use a ratchet with a 13mm socket to remove the two nuts holding up the skid plate. Then, use an 18mm socket to remove the remaining 4 bolts. Be careful that the skid plate does not fall on you!
Step 2. Remove Fill Plug
We remove this first because if something goes wrong and you are not able to remove it, you still have your fluid in the transfer case. If you drain the transfer case first, then you cannot get the fill plug off—you will then be in a jam! Another reason to remove the fill plug before you drain the T-case is that the oil will flow out easier.
Start by spraying brake cleaner around the fill and drain plug; use shop towels to wipe away the leftover brake clean. Next, use a 10mm hex bit socket with the ratchet to remove the fill plug.
Step 3. Remove Drain Plug
Position the oil catch pan under the transfer case drain hole. Slowly remove the drain plug with the 10mm hex bit socket with your ratchet. The oil will come pouring out all at once; try and keep the pan under the drainage.
Step 4. Install Drain Plug
Once all the oil has drained out, we can reinstall the drain plug. Wipe down the drain hole threads with shop towels. Clean the drain plug with brake cleaner and wipe it clean with a rag. Apply thread sealant to drain plug, and re-install it into the T-case with a 10mm hex socket. Finish by torquing the drain plug to 21 ft-lbs with a torque wrench and the 10mm hex bit.
Follow the thread sealant manufacturer’s instructions for cure time before proceeding to the next step of filling the transfer case with new ATF+4 Fluid.
Step 5. Fill Transfer Case
Once you have met the thread sealant manufacturer’s instructions for the cure time, we can proceed with filling the transfer case with the new ATF+4 Fluid. The transfer case will take a little less than 2 quarts of fluid. Open a quart of the ATF+4 Fluid and attached the fluid pump to the bottle and put the fluid pump hose in the fill hole. Begin pumping until you empty the first quart of fluid then switch the pump to the second ATF+4 Fluid quart bottle.
Pump the second bottle in until the fluid reaches the bottom of the fill hole then remove the hose and put the lid back on the bottle to save for next time. If it overflows a bit, that is okay! Stop pumping and let it finish overflowing. Then wipe off excessive fluid from the threads in the fill hole with shop towels.
Step 6. Install Fill Plug
Almost done! It is just a matter of putting it all back together. Apply thread sealant to the fill plug threads and then install the fill plug back in the fill hole with the 10mm hex bit socket and ratchet. And finally, torque the fill plug to 21 ft-lbs with torque wrench and 10mm hex bit socket.
Follow the thread sealant manufacturer’s instructions for cure time before starting the vehicle.
Step 7. Install Transfer Case Skid
Now that your transfer case is filled and closed up, we can re-install the transfer case skid plate. Put the skid plate back in position and tighten down the 4 bolts you took out previously with the 18mm socket and ratchet and torque them to 55 ft-lbs. Install the 2 nuts that you took out previously with the 13mm socket and ratchet and torque those to 48 ft-lbs.
Great job! You have completed this very important scheduled maintenance yourself and saved a bunch in mechanic labor fees. Plus, you get the satisfaction that you handled this yourself! Make sure to bring your old ATF+4 Fluid to a local auto part store for safe recycling. Keep up the good work. Now go have some fun out on the trails!