I do my own..
The fluid in the transfercase (I assume this is what you mean) Is ATF+4... and it is expensive, but I think it only takes a little over a litre I think... Maybe $6 a quart American Dollars!!
All you need is a 10 mm allen wrench pull the drain plug (lower plug, then the fill plug) drain, then add new fluid, Done!
As for the Trnny, it is harder, but you can do it yourself too, I do not know how much the 42rle takes for a change. You will need to drop the pan for this job. You can get aftermarket filters 2 of them, one unbolts with a 8mm socket (I think) the other is like an oil filter. Then some RTV for the gasket, redo the pan. Then fill her back up with the right amount of fluid... sounds worse than it is, trust me, had to do it on the trail once
