I am looking for the procedure how to the replace the differential oil, transfer case, and transmission.

type oil, and quantity.

 

The differential only has a fill plug...no drain. So, it's a matter of getting a new fill plug, sticking a tube into the differential and aspirating whatever volume you can get, and refilling with the SAME VOLUME you removed. Unlike MOST differentials, this is NOT a "fill until it runs out" process. It will be over-filled if you fill until it runs out.. The differential fluid is a 70w80 concoction that costs about 80.00 for half a liter. When I did the two F60's I've had, I believe I was able to get right at 350 mL aspirated out of each one. So, 350 went back in. No fluid ran out of the fill hole of either one.
8-speed auto is what both of my F60's have. I did a drain-and-refill. I did NOT have the correct tool to bring the trans temp up to the specified temp where the standpipe defines the correct level when the car is running (and I believe in park after shifting through the gears). Another hard thing about doing it this way is the car is supposed to be running...but you have to take the airbox out to get to the fill plug. I guess you over-fill it so you don't have to go back in and take everything apart again if you didn't have quite enough? Expensive fluid to purposefully put too much in. Instead, I did a similar drain, measure, and refill with exactly the same volume of fluid...and both the drain and the fill fluid were exactly the same temperature. I did this by draining the fluid after not driving for over-night, and the new fluid was stored right by the car. Doing it this way, I can drain about 2.75 quarts. I put that much back in...go drive a while, and repeat the overnight parking and do it again. I probably only replace about 1/2 of the total volume. But, these are "lifetime" fluids, so what I do is better than nothing.
That leaves us with two more fluids. Transfer case and "Hang-on-clutch" (assuming you have All4 system). I've never done either because the instructions I find say the viscosity of the new fluids must be programmed into the computer after their respective changes. The transfer case fluid is going to be an "aspirate and refill" similar to the differential. I'm not sure about the Hang-on-clutch (this is located just in front of the rear differential). If I end up keeping the car for what I'd guess would be 75,000-100,000 miles, I'll probably have both of these done at a shop at about 50,000 miles. Again, both are "lifetime fluids", although I certainly don't trust the transfer case fluid to last in very good condition much past 100,000 miles.
The drained Rear Diff fluid was very nice in appearance, as was the transmission fluid....both looked very much like the new replacement fluid. Both cars were done with about 30,000 miles on them So, at 30,000 miles I'd say you are WELL ahead of taking good care of those fluids. Perhaps 50,000 miles would be more than sufficient.
Hope this helped!

 

Yep more info here on it:

https://www.northamericanmotoring.co...placement.html

 

Also note that my 2019 JCW Countryman compared to my 2020 JCW Countryman, there was a change in Transmission fluid from ATF 6 to ATF 7. I know the 2020 has a much firmer shift feel...so there is perhaps a different friction coefficient used in the two versions of ATF. Make sure you get the right one for your vehicle.