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Check for lockout hubs on the 4WD.
If it still has the original fixed hubs, its probably an uncoverted NP203 that will make a great truck for snowplowing. It can be left in H all the time and will be an all-wheel-drive truck that lets you make turns, run on and off pavement, etc. If you put it in HLoc it will then be standard 4WD, where you really should be on dirt or snow to prevent driveline binding.
If it has locking hubs (there will be a switch on the face), someone has probably added a part-time kit to the NP203. Many folks did this because they thought the full-time setup took away gas mileage. However, the part time kit does have disadvantages.
- You no longer have AWD, so during plowing you may have to go in and out of 4WD when going from pavement to snow.
- The part time kit also disconnects the internal pump in the NP203 transfer case when its in 2WD mode, so you have to run it about once a week in 4WD to make sure the oil circulates completely and lubes the transfer case.
Also remember that GM recommends 10w30 oil in the NP203, not gear lube or automatic transmission fluid.
Bruce
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