Section 68 (Automatic Transmission Diagnosis - 4L80-E (Diesel)): Identification: Transmission
WARNING: This page is about a different car, the 2002 GMC Cab & Chassis Sierra and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Transmission is identified by metal identification plate attached to rear face of transmission case. See Fig 1 .