The case design of the DCT 8-speed transmission (RPO M1L) (Fig. 7) in 2020-2023 Corvettes is being updated toward the end of the 2023 model year.

A new Die 3 transmission can be easily identified by the 4 fasteners along the front edge of the sump pan. (Fig. 8, right)
The previous Die 2 transmission has 6 fasteners along the front edge of the sump pan. (Fig. 8, left)
Serviced transmissions will also begin to migrate to this updated design for older model years and will require additional parts to be ordered when used in an older model year.

Die 1 cases were originally produced with a stamped sump pan with rails. The stamped pans were replaced with the Die 2 cast pans. If any repairs were needed on a Die 1 transmission, it is possible to find a Die 1 transmission with a Die 2 pan installed, which can be identified by comparing the Die 1 and Die 2 bolt patterns. The Die 1 transmission sump pan has 15 bolts (Fig. 9) and the Die 2 cast sump pan has 19 bolts. If the Die 2 pan is installed on the Die 1 transmission, there will be holes in the pan without bolts.

TIP: For track use, Z51-equipped Stingrays with Die 3 cases no longer need the additional 2 quarts (1.89 L) of transmission fluid.
TIP: The canister filter for regular maintenance remains unchanged.

Refer to Bulletin #23-NA-156 for more information.