there "should" be a sticker on the inside of the drivers sun visor.

 

Im 99% sure you need to be in neutral to shift the transfer case into neutral or 4L, you also need to be stopped to do this. Every 4x4 I've had, this was the procedure.

 

It depends. You can shift into park and then shift into 4L. BUT, if you shift into park and are on a hill, you may have a problem. I am sure you know how hard it is to get it out of park on a steep hill if you do not set the parking brake first. That's because there is a lot of strain on the driveline trying to hold the truck on the hill.

Same with the transfer case. The best condition to shift the transfer case to any mode, in or out, is to not have any strain on the driveline when shifting. This can be a problem. If you get the truck all bound up and decide to shift into 4x4 or 4L, you may have to shift it in neutral, and rock the truck back and forth to get the transfer case to shift. That's why it's best to "predict" when you might need 4x4, lock the hubs in and put it in 4x4 before you get into trouble.

Putting the tranny in neutral will work most of the time, but you still may have to play with it a little bit to get it in.

 

Electronic shift transfer cases have safeties that won't let you do things the truck doesn't want you to do. Most of them will not shift into low range unless you're in neutral. But lever-shift cases don't think they are smarter than you. They CAN be shifted in or out of any gear in any situations, but it you do something they don't like you can break things.

Franklin2 has it nailed. Shift when there isn't a load on anything. For shifting into low range generally the best way to do that is come to a stop, put the trans in neutral, then shift the t.case to low range.