Gladiators...when new are not always in 4low when you shift them into low. I was with a friend in a rubicon that was new and was having problems with lockers and sway bar doing the same... at first I thought it was some sort of glich... but I realized he was not all the way into 4 low... it held in "low" on flat ground...but as soon at it was tilted up it kicked out. I would go out on dirt... and engage the 4low again while moving slightly... I think the only way to get it to slip into 4low is either you get lucky...or you need to be moving slightly. You will notice that you can have it look like its in low... but it still can not be set back into low range until the right spot comes around and it slips in. Your sway bar, nor lockers will work until low range is fully engaged...so my best guess is that you were not fully in low range.
