I put this same washer/dryer in my 2007 3500 this summer. Inside the space for the unit up in the right corner it has an area that goes behind where the water lines and washer drain are. I bought a dryer kit from camping world and traced the diameter on the inside wall. I used a drill to cut a pilot hole thru the wall to the outside. Then I used a Roto-Zip saw to cut the hole for the outside flapper fitting. It came out great. I used some sealer around the hole and screwed the fitting to the outside. I put the dryer hose on the fitting and then put it on the dryer before I pushed the dryer in the space. Make sure you don't crush the dryer hose with the dryer when you slide it in. Good luck ---- Butch