The dealer making the warranty repair is subject to audit on his warranty repairs and can be charged back for his submission. If you are taking a new truck to a dealer other than the selling dealer immediately after purchase, it is not hard to understand that dealer's hesitancy. If the manufacturer calls for the replaced part and determines in their opinion it is not warranty, the dealer will eat the part and the labor. You did not buy it there and that dealer would be prudent to make sure they are going to get paid.