Unfortunately I did not get an owners manual with my 02 2500 HD 4x4, with the Dmax and Allison trans, so I was hoping someone could tell me how to use the push button "tow mode" on the gear shifter lever??? I will be towing a 16' gooseneck on occasion, and would like to know how that works, and when/how to use it? In other words, do I just use it for going down hills, up hills, both, do I just leave it on when ever I have the trailer attached, or what? Thank you kindly for your time, and expertise, I really appreciate the help!