This bulletin applies to 2008 Cadillac CTS vehicles equipped with the 60L50 automatic transmission, where the issue involves no forward or reverse, an no input or output speed signal after a valve body replacement.
This may be caused by the installation of the incorrect center support fluid passage seal or upper valve body assembly. The center support fluid passage seal for the 6L50 is approximately 5/16-inch (8 mm) taller than the seal used on the 6L80/6L90 transmission.
The 6L50 seal can also be identified by the metal tabs or “wings” extending from the ends of the seal. The shorter 6L80/6L90 part will not seal the valve body to the center support, resulting in an internal fluid leak.
Also, the 6L50 upper valve body center support oil transfer holes are in a different location vs. the 6L80/6L90 valve body. Installation of the 6L80/6L90 upper valve body may result in an internal fluid leak, with no forward or reverse.
Finally, installation of a 6L80/6L90 upper valve body will not place the input and output speed sensors close enough to their respective drums to generate a speed signal.