If you cannot find your data tag, or if the online system requires a login you do not have, an authorized dealer can assist you. Provide them with your vehicle's VIN; in many cases, commercial truck dealers can cross-reference the VIN to pull the factory-installed transmission serial number.
Several scenarios can complicate the process of performing an Allison transmission serial number lookup. Here are the most common issues and how to address them. Allison Transmission Serial Number Lookup