- Nationwide Truck Parts LLC. sells quality used heavy truck parts, used diesel engines, transmissions and more. We provide quality used heavy truck parts at a reasonable price. Every part we sell comes with a standard warranty and is tested prior to sale. We ship nationwide with same day shipping available. If you do not see the part you are in need of, give us a call as our inventory changes daily and we can locate any part you need. We sell Cummins, CAT, Detroit, International, MACK, Mercedes, Isuzu, Mitsubishi diesel engines and more.