The VX is always in 4WD, and you can change from drive (D) which uses all 4 gears, to 2 or 1 on the transmission which would not allow the vehicle to shift up the first or second low gears and therefore slow you down; its called engine braking. If its really steep then switching the transfer case into 4L ( 4WD Low) would slow the VX down even more. This is usually perfectly fine for a transmission and is usually the safest way to get around when wheeling; using your brakes downhill is not as controllable and as you know can temporarily or permanently damage them. Its still not good to redline your engine in this fashion, but you will still use your brakes considerably less to prevent that. Usually shifting gears is what damages them, so just staying in 1 is usually a safe bet (usually; make good judgments). Ask anyone in Colorado (or another mountainous area) about driving down steep grades; there's signs everywhere about engine braking for larger vehicles and advice to shift into low gear. They even have runoff areas for when you don't heed the advice and blow your brakes.

That's pretty much the basics, but let me know if I rambled too much.