You know the guy that built the truck intended it to be full time four wheel drive. General Motors wanted it that way, the rest of the truck us intended to support THAT.
I am nooooooo master of that stuff by ANY means BUT.
I've had mine awhile.
I've been HERE awhile.
I drive mine EVERYDAY.
From what I gather, cheap assed, stupid mother f*ckers were concerned about GAS MILEAGE and got sold the SCAM of converting their transfer case. Digest that, it's real talk.
When their "full time" factory front hubs FAILED (think wheelspin) the cheap assed, dumb f*ck way to fix them was to put locking hubs on instead. Again, real talk.
My case is not converted, but i have locking hubs. Between all of the involved parts, there are many possibilities of what is ACTUALLY goin on in YOUR truck.
My advice about an NP-203 is sound. Put it in 4Hi, lock the hubs and forget about it.
I avoid Loc but then again, i'm a city boy. My truck lives on concrete and mostly sees pavement.
My truck DRIVES BETTER in 4Hi with the hubs locked. Turns out with my available installed parts, that's the way it was intended to be. No wonder I like it that way.
I understand any "gas savings" is negligible FORTY YEARS LATER, I think you fool only yourself if you believe a conversion is going to save you any real money.
For the record, my case sticks in Loc also, lol.
I never, ever consider any of that stuff. I have set it and forget it.
I have seen with my own eyes, my truck spinning all four wheels in the mud. The "open side" spins at 50% speed of the drive side, & there is a lot of stuff going on with two open differentials for sure! When it switches sides you can FEEL it. It's wild!
Hope this helps..
If I didn't have manual hubs installed, i'd run factory parts in a HEARTBEAT.
But you know....previous owners...