Yes. It is easy to do, if you can do an engine oil change then you will not have any problems with this task.
You need a suction gun (to fill the gearbox and transfer case), a 24mm or 15/16" ring/open ender or socket, cotton rags and some old cardboard for a drop sheet and an oil drain dish. On the side of gearbox is 2x 24mm head diameter plugs, one drain and one level. The drain plug is on the drivers side at bottom of the gearbox and the level plug is on the passenger side roughly midway up the side of the 'box.
The transfer drain plug is on the passenger side and the level is at the back of the transfer case facing the diff. These are 24mm also. The transfer drain plug has a magnetic trap for ferrous material. Curiously, the gearbox didn't have one.
After a good run to get the oil nice and hot get under the truck (safety first here folks - use safety stands, chocks etc if needed. Those with a good suspension lift may not need to bother). Place drop sheets, clean around the level and drain plugs and use the 24mm to undo the drain and level plugs, catch oil in the drain dish (be careful the oil flows a fair way and can be quite hot). Allow to drain (say 10-15minutes).
Once drained, clean drain plug/s and reinstall - dont over tighten it is only alloy. Using the suction gun draw up the new oil and inject into the level hole/s. Repeat until oil overflows out of the level plug/s. Install the level plug bungs and you are done - a quick degrease and clean up and that's it.
The voices in my head may not be real, but they do have some damned good ideas.
If it's feral, it's in peril.
MN turbo lag? What lag??
99% of lawyers give the rest a bad name.