I am new to the Mack trucks , and don't have much experience working on them. I am looking to purchase another Mack (1998 ch600) and had a question about the odometer. The guy told me that it has around 800,000 on truck, but the odometer shows 270,000. I asked him why the odometer said different than what he told me , and he said that when you replaced a certain module for the electronic throttle that it would reset the mileage on the odometer to zero. He might be right but I am unsure because I thought the odometer/ speedometer where mechanical on these trucks. I am betting that the truck has a 1,270,000, But like I said I could be wrong. Can anyone help answer my question?