And you're saying that it doesn't move then?
I have an '02, 4x4 5.9L. Not that I need 4-low, but I shift into it
every month or so just to keep things moving. It's like this:
Shift into neutral.
Click the dial over to 4-low.
The transfer case clicks going into 4-high, then louder going into
4-low light comes on.
Shift back into Drive.
At that point, if my foot isn't hard on the brake then the truck takes
off. No wait and no slipping. Perhaps something's gummed up on yours
and the dealer doesn't want to mess with it?