From the Wikipedia site:
"A Mack truck with a gold-plated bulldog indicates that the entire truck is made of Mack components. Trucks with another manufacturer's transmission, engine, rear axles or suspension are given the chrome-plated bulldog."
"A Mack truck with a gold-plated bulldog indicates that the entire truck is made of Mack components. Trucks with another manufacturer's transmission, engine, rear axles or suspension are given the chrome-plated bulldog."