Bill, welcome to the site.

Not sure if the wiring changed on the 4L80E from the earlier years to the later years. It did on the 4L60E. Those transmissions needed to be a '96 or newer to work with the LS engine's PCM, or have the internal transmission wiring converted to the newer wiring if it is a pre '96. I think the 4L80E remained unchanged but I'm not sure. Hopefully someone will be along with a better answer.