jleamont Report post Posted January 4, 2018 Yeah, the Detroit DD13 has a 35,000 mile service interval. Five, not a synthetic oil change but a lighter weight would also help. Discuss with your local Freightliner dealer, just might benefit you. Share this post Link to post Share on other sites
STORMIN36 Report post Posted February 11, 2018 Apparently you have a gas generator. However, if it's a diesel, AMSOIL has a 15W-40 that I use in my generator and it meets the requirements of Onan. It provides 4 times the protection required by Onan and is designed for extended oil changes. Share this post Link to post Share on other sites
hermanmullins Report post Posted February 12, 2018 Welcome to the Forum, Good information. Herman Share this post Link to post Share on other sites
