About Us

Experience matters, building your trust for over 30 years!

Diesel technology has transformed vastly over the past 30 years and continues to evolve each day! Be it standard diesel repair, diesel maintenance, diesel performance or major diesel engine repair Rocky Mountain Diesel (RMD) has the parts and experience to help. We are the experts when it comes to diesel trucks and aftermarket diesel performance. Our ASE certified techs have worked on thousands of trucks, tractors, motor homes, and boats. You can trust us to provide the best diesel repair in Missoula! We welcome everyone, so come on in to your local family owned shop for the personalized care that you and your truck deserve!

Regular maintenance is the key to getting the most out of your vehicle. But you shouldn't have to sacrifice trust and peace of mind when finding a repair center for your diesel. We are a certified NAPA Truck Center.  NAPA Truck Centers are built around a quality standard where independent business like Rocky Mountain Diesel are invited based on integrity, qualifications and expertise. That's how NAPA ensures you get the best in class service that you deserve.

From routine maintenance to major repairs, we've got you covered. Our ASE-certified technicians use high-quality NAPA parts and provide exceptional work; work that you can feel confident about, knowing it's backed by our 12 month, 12,000 mile Nationwide Peace of Mind Warranty. With the largest network of independent mechanics in the U.S.


Our Start

In 1985 Bill and Priscilla Sherman started Rocky Mountain Diesel. They serviced the majority of the major trucking companies along with almost every diesel truck, tractor and boat in town. Kerry Costello received his degree at the University of Montana College Of Technology Diesel Equipment Technology program. After working for a local trucking company, he began to work for Bill and Priscilla Sherman. What he didn’t know - he was their retirement plan. After years of intense training, Kerry was told it was his turn to take over the business. In 2002 Kerry Costello and His brother Kevin Costello purchased Rocky Mountain Diesel. It continues to run as a family business with second generation family members receiving their training.