While driving, the transmission suddenly would not shift out of low gear.
What is your question?
Changed oil and serviced transmission, now it is in high gear, but won't shift. The "M" shift indicator light does not come on when I put it in Manual, most of the time. It comes on periodically, and when it comes on, the transmission will shift. Error codes are P0796 and P0971.
RepairPal Certified shops can diagnose and repair your 2011 Chevrolet Express 2500. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.