Section 3 (Overhaul - THM 400): Identification
WARNING: This page does not describe the selected car, but rather 124 other vehicles, including the 1991 Chevrolet Pickup, 1991 Chevrolet Cab & Chassis, 1988 GMC Vandura Special, 1988 GMC Vandura, and 1988 GMC Value Van. However, it is still accessible from the selected car via links, so may be relevant.
Transmission serial number is located on identification plate attached to right side of transmission case. See Fig 1. Number consists of model year, 2 letter model code, and production serial number.