Got new seal in and everything buttoned up. Job went well. A couple of comments I'll make are:
A) Get someone to hold front driveshaft gearset in place when starting fasteners for intermediate cover. Makes job a lot easier. The lovely Ms engatwork helped me
.
B) on the 2015 E350 chassis you can remove front d/s without breaking transfer case down. The youtube video I watched was in error in this regard.
Every 4matic with transfer case (differential) built into rear of the transmission like these will eventually have to deal with this d/s system.