Just did a quick check with Edmunds.com and not having all the options on the OP's truck, the trade in value was just under $29,000 for a clean vehicle with the miles he stated. This is a long ways from what the OP feels his vehicle is worth in trade.
Last spring, about a year ago now, I traded my 2002 Dodge/Cummins off on a new one ton Chevy diesel crew cab with 4 X 4. They showed me all the discounts off the sticker price (over $60,000) and then told me they would give me auction price for my trade. The big auction in Orlando drives the trade in prices for the SE part of the country. My dealer pulled up the auction info on the computer and then three closest sales to mine. They were real close to each other. At time point the difference between the two figures was all that mattered to me. I made them a slightly lower offer, which they accepted. I was told because my truck was a diesel, they would keep it on their used lot for a couple of weeks, to try and sell it. A gas rig would be sent to the auction on the next truck. Mine had 144,000 miles on it. The next day after the trade, my rig showed up on their internet site and they had priced my truck at $995 over, what they had given me for a trade. Three days later, it was listed as sold and was gone. The dealer made a small profit and a sales person made a commision on the sale.