Does 4high work like it should? If it doesn't, I would suspect that something is wrong with your front hubs. And just to make sure you know this, to engage 4low you have to have your foot on the brake and the truck in neutral, or if it is a manual you have to have the clutch pushed in I believe. If 4high works but 4low doesn't, I would suspect something in the transfer case broke. Also, if you do not have a limited slip in the rear, it is perfectly normal for just one tire to spin.
ok i thinks its my locks but i have no idea if the locks that i have r auto or manual they dont hav n e cables attached does n e body hav a pic of their auto lox to c if theyr like mine thanx in advance
I am not 100% sure, but I am pretty sure the 2000's are live front axles (there are no locking hubs). The only hubs I know of after 97 are vaccum hubs, but I am pretty sure they were only used from 98-99. Unless you have L/S or a locker only one front wheel and one back wheel will spin (because of the differential). Even L/S axles will allow one wheel to spin if the other wheel is grabbing something pretty hard and the truck is buried enough, because it is LIMITED slip not NO slip.