I get a lot of people that ask me what their service (oil change) intervals should be. There really are a lot of variables. With used trucks that are used in the field you will want to make sure you change your oil much more often since they are exposed to so much more dirt and elements. it also depends on whether or not you use Synthetic Oil. Depending on the brand you can go out up to 10 to 12,000 miles, but you will raise your cost per oil change.
Do you live in colder climates like northern Wisconsin, Michigan, or Minnesota? If so that may change your intervals a bit too. I have always felt that oil is cheaper then a new motor or transmission. The older the car, i think the more important it is to stay on top of that service. There are a lot of options out there but if you want some honest to goodness great advice talk to Kevin. He will always steer you in the right direction.
Our oil change here is 29.95 with a full multi-point inspection, and tire rotation in August. If you're ever in need be sure to get in touch!