There are different approaches you can take. The key difference is whether or not the truck broke during the day or the night. If it’s nice and bright out, you can just look up “diesel repair St. Louis” — replace St. Louis with whatever city is closest to you — and get a tow truck to take you there. Or you can use a platform like https://www.truckup.com/cities/st-louis to find mechanics who can get to your location to provide roadside assistance.
When the truck breaks in the middle of the night the situation is a little trickier. A lot of tow companies operate 24/7 to help clients with just this type of emergency, but finding one of those to call in an area you’re not familiar with can take a bit longer. Especially if you’re in an area with less cell signal. Remember, if you’re stranded and can’t contact help, you can get in touch with 911 or the local police and ask for assistance. They’ll give you directions.