What causes a transmission not to shift gears?
What causes a transmission not to shift gears? Transmission fluid An AT with dirty or low fluid will not shift into gear. Add new ATF using a clean funnel if it's low. If your car goes into gear after adding ATF, then your transmission was low on fluid, most likely due to a leak. Your next stop should be your repair shop so your mechanic can check for leaks. Why does my car not shift into third gear? Such a problem is automatic transmission won’t shift into 3rd gear. The transmission shifts into the first and then to second gear...