well my check engine light is now constantly on and my transmission seems to be stuck in 3rd gear indefinitely - this seems expensive. Any tips?

id like to get the car computer scanned for codes, do mechanics do this service free?

more importantly, my car has the 8yr 80,000 mile power train Chrysler certified vehicle, but i have to get the paper signed by previous owner and I - if anybody can help me understand this process I wont have a strange feeling in my gut anymore