I agree, most folks don't use 4LO often enough. Some mud holes will be easier to traverse with momentum, that is, a slightly faster forward speed or enough to get to the other side without losing control. Deeper holes that you're unsure about are better taken at slow speed, and that's where low range helps. You may have to shift into 2nd to keep from over-revving the engine.
Most automatic trannies like the E4OD or 4-speed will stay in 1st gear if you put the shift lever into "1", but will upshift out of first if you just leave the shifter in D/OD or normal high gear. SO, if you shift the tranny into 1st and the t-case into 4LO, you might be doing 3000 rpm's and only driving 5 mph. IF you select high gear/OD and use 4LO, the tranny will upshift into 2nd with enough forward speed or rpm. You can always turn the OD (overdrive) off, so the tranny won't shift past 3rd.
And it's much harder on the drivetrain if you go over 40 mph in 4WD, so take it easy. It's usually better to let the truck's own power pull you thru the mud so you have better control of the steering. There's less chance of spinning the tires and losing traction, too. If you get stuck, then you may need to power out of the mud hole in 4HI and 2nd gear. My $0.02
>-
