A W Diesel Service, Inc. Check out our dynamometer to test your medium to heavy duty truck for Performance Diagnostics Engine break in and more! Ask for Eric to set up an appointment! 15 Highway 13 East 701-678-2132 AW Diesel Service Gwinner, ND aw-diesel.com A W Diesel Service , Inc. Check out our dynamometer to test your medium to heavy duty truck for Performance Diagnostics Engine break in and more ! Ask for Eric to set up an appointment ! 15 Highway 13 East 701-678-2132 AW Diesel Service Gwinner , ND aw-diesel.com