All engines and transmissions are stamped or laser etched with a partial Vehicle Identification Number (VIN), which was derived from the complete VIN. A VIN derivative contains the following nine positions:
Position  | Definition  | Character  | Description  | 
|---|---|---|---|
1  | GM Division Identifier  | G  | General Motors  | 
2  | Model Year  | X  | 1999  | 
3  | Assembly Plant  | 1 E Z J G R  | Oshawa, Ontario Pontiac, MI Fort Wayne, IN Janesville, WI Silao, Mexico Arlington, TX  | 
4-9  | Plant Sequence Number  | --  | --  | 
A VIN derivative can be used to determine if a vehicle contains the original engine or transmission, by matching the VIN derivative positions to their accompanying positions in the complete VIN:
VIN Derivative Position  | Equivalent VIN Position  | 
|---|---|
1  | 2  | 
2  | 10  | 
3  | 11  | 
4-9  | 12-17  |