Try your local parts house that sells "A-1 Cardone" reman products. I called my old parts house that we dealt most with and they looked it up. 05 Ram 2500 or 3500 part number is 27-7616 Retail price is 325.00 with a core charge of 175.00. He said that there were none in his warehouse but the old box could get rebuilt if it was sent in.
Hope this helps.
http://www.cardone.com/English/Club/default.asp