I sold my truck to someone and forgot to get a receipt. Did I need to write "As Is"?

She didn't want to test drive it, and paid cash. We filled out all the DMV paperwork and everyone signed the title etc... Then she gets on the freeway and the cruise isn't working so she said she's taking it to a mechanic and wants me to help pay for it. Is there any legal standpoint here? What should I do?