I am selling my 4500. It is in great condition. Has the duramax/allison. It is a 2006 model that some think is the best year model. pre pollution devices. The truck has air ride seats and a/c. The 4 wheel drive system works great. just over 20,000 miles on it. Comes with a custom 3" receiver hitch and combination ball-pintle on it as well as brake controller. Under bed tool boxes on both sides. It is a great truck that will make someone very happy. $27,000.00, PM me for a phone number if interested.