I changed the gear oil in the transfer case and both differentials this afternoon. The transfer case was much easier than I expected. I used the 1/2 inch breaker bar shown in the 1rst photo to remove all fill and drain plugs.

I was able to push the E brake cable out of the way just enough to get the breaker bar between the cable and the T-case and the fill plug came out easy. I then removed the drain plug and the gear oil that came out needed to be changed. There was some metal on the magnet. I cleaned the plugs and wrapped with Teflon tape. Put the drain plug back in and filled with Full Synthetic 75/90. The T-Case held almost 2 1/2 qts. I used a pump from O'Reilly Auto Parts that fits quart and gallon jugs for $8.99. The T-Case took about 35 minutes.
In 2nd photo you can see the fill plug removed. The 3rd photo shows the location of the fill plug in the T-case and the 4th photo shows the drain plug removed.

The differentials are a piece of cake. make sure you can remove the fill plug and then drain. The 5th photo shows the location of the fill plug on the differential. The front and rear are the same. The gear oil in both needed to be changed. I used the same 75/90 for both. Both held about 2 qts.

If you have been putting these maintenance items off because you don't have experience working on Disco's, don't wait anymore as this was as easy as changing the oil.

 

really makes you stop and think, "why didn't I do that sooner?" Swapping out with synthetics in your driveline is the easiest way to gain MPG.

 

Next item on my list is to change the transmission fluid. I will post some photos of that too. I forgot to add that the whine at cruising speed has been much reduced with the fresh gear oil.

 

What ATF are you going to use for the tranny.
Little late/expensive to use synthetic, might consider Vavoline's extended mileage dextron 3

 

X2 on what Mike said. That is what I am running.

 

I haven't thought about what fluid to use in the tranny yet, but Valvoline sounds good to me.

 

great pics guys. did your transfer case put of and awfull burt smell before you changed transfer case fluid.

 

ok . so i changed the transfer case fluid. i changed it because i thought it was time and when i removed bottom plug only an ounce or two came out. the transfer case smelled burnt when running. i filled it up and now it is leaking from somewhere in the front really badly. when i bought the car i noticed a lot of gunk under there from a possible long term leak somewhere. but for the 20,000 miles ive owned it, it never had a leak like this. just a drip every morning. what do i do now any tips other than parking it in south dallas with the keys in it. thanks

 

year, model, mileage?

 

Not at all normal or good. Seriously only a couple ounces came out? Were there metal chunks on the plug magnet? This is not good hopefully you caught it but I would plan on replacing the transfer case sometime soon.

I think you found out why your case was empty. Try to power wash off the gunk to find your leak and fix it. Let us know exactly where it is coming from.