[DirtyLarry]

NP2 is a manual shift NP261 and the NP8 is the NP246 electric shift Autocrap tcase. You want to replace a reliable manual shift with an electric shift??

How did your NP2 fail? Chain rub a hole in the case? That happens to the NP8 and NP1 (NP263) as well. Personally, I wouldn’t swap any electric shift tcase into anything other than a boat to use as an anchor but if you must you will need the control head, transfercase control module and study a circuit diagram to wire everything in correctly. I beleive the front axle disconnect is also different on the NP8 Autocrap trucks as well. Different driveshafts will also be needed but the tcase itself will bolt right up to the transmission.

I wouldn't do it. Electric shift tcases are as reliable as an anvil made of legos.