4wd, gotta do the front and the rear at the same time if you have electronic push button. With the electronic, the front drive shaft spins all the time. Not sure if you would get bound up or not, but i wouldn't want to find out the hard way. If you don't use the 4wd that much, i would go with a Yukon or Standard Gear up in the front because the front set only runs around $120.