Dash and transmission problem. Electrical or Ignition Switch problem? Please help !

I start my 2000 Z71 the dash gauges and shift indicator stop working. At the same time my tranny seems to be stuck in one gear and wont upshift or downshift. Then the service engine soon light comes on. The problem is intermittent because sometimes shutting down and restarting fixes the problem, but not all the time. I can go days or weeks without having any trouble then all of a sudden it starts doing it again. Checked all the fuses and checked battery cable all is fine. Could this be the ignition switch?

Welcome to AF on your first post.
Lot of computer controlled stuff and switches and wiring involved there.
You will need to get it on a transmission and engine and body capable scanner to check it out and find the problem.
If you can get the code or codes post back code no.
MT