I have a 99 silverado with the NP 246 electronic transfer case. I was under my truck checking for and exhaust leak when i noticed my front driveshaft is engaged when in 2 HI, but its not in 4wd as in the front axle isnt engaged. Could it be the transfer case motor or the switch on the dash or both? is there a way the check the tcase motor without removing it? Or to test the switch on the dash?

 

I have to do some research about the from drive shaft spinning. But unless the 4WD selector is in the 4WD position the IFS will not engage. There is a solenoid (thermal switch) on the IFS that engages a clutch in the IFS which then sends driven power to each front axle.

I almost think the front driveshaft would “freewheel” until 4H or 4L is selected. In the transfer there is a electric solenoid that engages either 4L or 4H.