my guess is bc you weren't moving and just happened to be in a position where the teeth of the gears weren't lining up right...putting it into neutral allowed the gear to freely turn where it needed to go and engage. Despite the options and what the manual says, the surefire/safest way to shift into high or low is to be in neutral and just barely moving.
you can go into 4 hi "on the fly" but I will never do it in my truck going faster then 10 mph
2013 F-150 Sterling Gray STX SuperCab
4x4 | 5.0 | Tow Package | Spray On Liner | Wheel Well Liners
1.5" AS level | 17" Raptor Wheels with 285/70 BFG KO2
HD Head and Tail Lights | UWS Low Profile Box | Flowmaster Super 44
Last edited by TheRangerOfDanger; 03-05-2014 at 02:42 PM.