MOST 2000's came with live axle.
Look under the lug nut center cap. If there is a 32mm nut, it has live axle, not PVH hubs, which are problematic.
I interpreted his post as 4hi and 4Lo never come on.
2Hi to 4Hi is a switch on the fly (no foot on brake, clutch in, zero speedo crap), so it obviously isn't working (no 4Hi light on). Therefor, I presumed it is the shift motor. Tap it lightly with a screwdriver handle. Also check the fuses, #3 under the hood (mini, 20A) and fuse 6 and 26 in the cab. (If 26 were blown, you'd have other issues).
On my 2000, you can hear the shift module click. If you aren't hearing any click (in the quiet cab, motor off, key in Run) then it is probably the 4wd Shift Module (or a fuse).
Oh, and Welcome to The Ranger Station!