2008 Expy...I've read that the 3.31 plus the 6-speed tranny is all you need for max towing. True or false? I think I'd want the 3.73, but I do not see 3.73 as an option anywhere online.

I see HD trailer tow in the list of options available on the 08 Expy, but I do not see an 3.73 in the list. Was 3.73 available at all in the 2008 ?