4-LO is limited to 30 mph because of the reduced gear ratio. 4-HI, iirc, is the same gear ratio as 2-WD. (read your drivers side sun visor sticker)
4-WD, HI or LO, is for low traction situations, so are slower speeds.
Speaking of that damn sticker. Does anyone know how to get that thing off without damaging the head liner?
