Find out what type rear end is in the EB. If your pulling something with heavy tongue weight, a full floating axle is advisable. as far as a tow haul, I never was able to find that feature on a van. Maybe it's the way SMB ordered my van but I've only seen it on pickups (I could be wrong). All I have is a switch to turn the OD on and off and I asked for the tow package.
2006 Ford 6.0PSD EB-50/E-PH SMB 4X4 Rock Crawler Trailer
My van came factory equipped with tow haul. I just assumed if you ordered the tow package you got tow haul. Since I bought the van used I'm happy I got an option that is rare and desirable. In reviewing the original Dealer spec sheet it does appear the tow haul is a seperate option.
"Tow on" is the same thing as "OD off". It just won't let the trans shift into the tallest gear. Not sure when or why Ford thought to change the language of it. My van is an 06 and has the "Tow" tranny stalk. A 2000 F350 diesel I used to drive had the "OD" stalk. So, same function with different wording.
2006 Ford E350 6.0 SMB 4x4 Modified EB45
I just looked at the SMB in Santa Paula again. They had the original window sticker. It some kind of transmission option but it said "without tow haul". The cost for this option was about $380 and I don't remember what it was, only that I was disappointed that there was no tow haul. So this '05 diesel has 5 spd and OD but no tow haul.
I have both trannies -- My Excursion with "tow/haul" mode when engaged will automatically down shift when needed on steep down grades. My SMB with tow package has "O/D off" and will just not shift into the higest gear. They are definitely different. I am under the assumption that only the V10 SMB's have the Tow/Haul and that all Diesel's have "O/D off" only.