How to Service a 4x4 Transfer Case

We are a group of ASE certified technicians that have created this guide for you to save money when doing the job yourself, or see what you are paying for when taking your car into a shop. In this guide and video we will show you how to service your transfer case, which is easy to do with everyday tools.

Why Service?

A transfer case is designed with a large heavy duty chain, bearings, shafts and gears which rotate and switch positions to achieve the various modes of operation such as 2 Wheel High, 4 Wheel High and 4 Wheel Low. Much like a transmission or engine, the transfer case uses oil to lubricate and cool the unit while it is in operation. In time and usage the fluid can become contaminated with small metal particles which can shorten the transfer case's lifespan, which is why the fluid needs to be changed.

What's the Cost?

Typically, replacement fluid will cost between $20.00 and $40.00 on Amazon or an auto parts store (US). Labor time can run between .8 and 1.5 hours at a shop or dealership. If exact times or procedures are needed, you can ask our experts to supply you with the information (free), or consult an online resource such as AllData DIY (pay), but this guide and video should be sufficient in most cases.

Let's Get Started!

1. In some cases, the vehicle will need to be raised up and put on jack stands to gain access to the transfer case drain and fill plugs.

2. Using a flashlight, locate the drain and fill plugs in the transfer case which are usually near the bottom and side of the unit, the fill plug will be slightly higher than the drain plug. Here is what they typically look like in the image below.

transfer case fill drain port

3. Remove the fill plug to make sure it is not seized, this is so you can refill the unit once it has been drained, also it will help the fluid drain out once the drain plug is removed. A little fluid may drain out which is normal.

remove fill plug

4. Loosen and remove the transfer case drain plug, have a fluid catch basin ready, also have shop towels handy to wipe up any spills.

drain transfer case fluid

5. Once the fluid has stopped draining use a shop towel to wipe the surface clean, this will help the plug to seal to the transmission case without leaking. Some drain plugs will have a metal sealing washer which should be replaced when doing the job.

wipe clean

6. Reinstall the drain plug and tighten to specifications, in this case the torque spec is 19 foot pounds.

7. Use a fluid pump which is available on Amazon or the local auto parts store for about $12.00, refill the transfer case using the manufacturer's specified fluid type, in this case it's Motorcraft, MERCON ATF Capacity - 1.9L (4.0 pts.). Once excess fluid starts to pour out of the fill port, the fluid level is correct.

fill transfer case

8. Use a shop towel to wipe up any remaining fluid and reinstall the fill port plug and tighten to specification which is again,19 foot pounds of torque.

tighten transfer case fill port

Watch the Video!

Please watch this video of the job being done, then continue with the guide to glean additional helpful information.


Our certified technicians are ready to answer transfer case service questions for free. We hope you saved money and learned from this guide. We are creating a full set of car repair guides. Please subscribe to our 2CarPros YouTube channel and check back often for new videos which are uploaded regularly.

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