Can i haul a vehicle on a car trailer with out turning off my overdrive ?

[DoughBoy]

I have a 1989 dodge ramcharger I want to haul 240 miles with my 2006 Durango with a 4.7L engine and a average size car trailer... do I really need to turn off my overdrive?... or can i keep it in overdrive without ruining my transmission? I need some help from someone with experience... thanks