This is what I have learned so far.
To handle the increased towing, the Max Tow package will add a beefed up rear axle with a new 4. 10 gear ratio, new rear-axle pinion, new helical gears, upgraded bearings and an aluminum differential cover with large cooling fins. There's also a new water-to-oil transmission cooler and new power steering cooler to help manage the higher trailer towing ratings.
This part may be for cab & chassis only. The Max Tow package includes a new transfer case gear set and chain and sprocket upgrades, recalibrated transmission software and an enhanced collection of thermal management devices.
A mechanic at a Dodge dealership says it will fit. I read this on another fourm, I haven't seen this for myself.
Maybe when Slow Six goes to pick up his NEW truck he could take a tape measure with him and let us know what he thinks.