Truck Transmission Identification Number For "Service" Usage

The following system will be used to identify service transmission assemblies domestically produced. This number system applies to complete service transmission assemblies only. Transmission cases are no longer identified. Manufacturing plants will number each service assembly as it is produced. The first letter will designate the GM division which produced the unit - "C" (Chevrolet).

The second letter will indicate the type of unit - "T" (transmission). The number following the letter will designate the model year - "5" (1985). The last five (5) digits specify the service replacement sequence number. The group of numbers to be used by Chevrolet Manufacturing plants are as follows:


Plant Serial Sequence

Chevrolet - Parma Transmission Plant 00001 to 14999

Chevrolet - Muncie Transmission Plant 25000 to 99999

Hydra-Matic 00001 to 99999

Hydra-Matic transmissions will be numbered with the letter "H" regardless of the GM division using the transmission.


Example: Number CT500175 designates Chevrolet transmission, year, and 175th unit produced for service at Parma.


Upon completion of the serial sequence, the plant will reuse the above numbers using a letter prefix, such as A, B, or C to indicate late production transmission; for example: CT 2A0001.