To be able to quickly sell your truck, you will need to get an appraisal. One such appraisal tool is available from Edmunds and there is a blue book site for trucks too but the report costs a fee. There are the National Appraisal Guides and in particular, truck guides, provided by the National Automobile Dealers Association (NADA). Once you have done some research into the costs of a comparable truck like yours, you can find a target price with which to use as your sales price. Selling a truck almost implies a certain type of buyer who knows what they want and have an identified need. A clean engine compartment shows that you've definitely taken good care of the truck as well as having a clean underbody.
Potential buyers will scrutinize all aspects of your vehicle because they don't personally know you and they want to ensure that they are getting a fair deal. There are many ways in which to sell a vehicle but not all will facilitate a quick truck sale. You would better be served by identifying vehicle or truck clubs across the nation that sponsor events and provide news to their members.