Picked up my car Friday night, and after driving it on the highway for about 30 minutes I noticed at around 55 mph the tranny wasn't shifting the rpm's were going over 4000 rpm's and not shifting...Now the check engine light is on. Now I can't go over 30 mph..SUCKS

Anyone else having a problem like this with their automatic??
I'm planning on calling the service dept first thing in the morning to have this checked out..