The drain plug for the transfer case on my Rodeo with a MUA tranny is obvious, right on the bottom of the transfer case, with a nice hole cut in the skid plate for draining through.

The drain for the tranny itself is located on the back SIDE of the tranny, over towards the driver's side of the tranny, NOT on the bottom, but on the side towards the bottom. Though there is also a hole through the skid plate there, this turns out to be poorly placed and a PITA.

BEFORE you drain, make sure you can get the fill plug out. Again, on my rodeo this is a really tight location, between the tunnel and the transmission on the passenger side about halfway up and halfway down the length of the tranny case. In order to get to my fill plug, I have to use two long socket extensions and fish them through the frame and torsion spring, and of course, the last time I had a it done in the shop the sumbitch is really torqued down on there...

I recommend having a very large drain pan, and by large I mean wide. As you drain the transmission, the oil that is supposed to go through the hole in the skid plate actually goes all over the skid plate and frame member and comes dripping down all over.

To refill the transmission, I have a hand pump that fits on gallon oil jugs (or five quart if you buy your oil at Walmart), and a long tube to go up to the fill hole. Again, if you overfill the oil comes out of the fill hole and drains all over the frame and exhaust and makes a real mess. This is almost (almost) one of those very rare jobs that I would pay someone to do, because without a lift it is almost impossible to do. I put the front up on ramps and jack the rear up to match the front height, and this gives me enough room to do the job.

The good news is that it only has to be done every 30K miles... for me if it is mostly all highway I extend this interval out to 45K miles by using synthetic oil.

Don't forget to do the diffs and grease the drivelines while your under there...