Corey, you WILL NEED the Double Cardan U joint front Driveshaft!!! I didnt have one in mine and I damaged the front output shaft bearing in my Tcase!! As far as all Escalades go, they ALL came with the NP246 Auto Trac Tcase!! And that front driveshaft ALWAYS spins regardless if in 2HI or 4HI, because thats what enables you to shift into 2HI to 4HI while moving up to 50 MPH and the Auto feature all it does is lock the fron actuator and apply clutch pressure to the front DS when the TCCM senses slip in the rear wheels. I dont suggest running in auto 4WD because of worse gas mileage and more wear in the clutches.
I ended getting a good used Double cardan DS on craigslist, so just search!! In the meanwhile run without the DS until you find one if not risk damaging the Tcase!!!