Pretty sure it says in the manual that you have to flat bed tow, you're not even supposed to tow it with TWO wheels on the ground, let alone four.
With the engine off the transmission won't pump enough fluid and you would be burning up bearings. Additionally, the IWE hubs on the front wheels would engage, and the front drive axles/diff/shaft would be spinning (albeit freely in the t-case) as well which would be a lot of additional resistance & unnecessary wear.
Hmm, although I did see another posting saying that it was possible with the t-case in neutral. Maybe I'm talking out of my ass. Either way, manual says "no", so I probably wouldn't do it.