Car will not shift into overdrive

2011 CHEVROLET AVEO
150,000 MILES • 4 CYL • 2WD • AUTOMATIC
Avatar
STEVEN KEITH
  • MEMBER
  • 1 POST
My valve cover gasket went out filled my spark plug wells with oil. Changed gasket and plugs cleaned wells and the plug rail the same time my gasket went out the car was missing out avid quit shifting into overdrive well the car is running a lot smoother but will still not shift. I am at a loss. Please help.
Oct 28, 2018 at 10:02 AM
Advertisement
Avatar
STRAILER
  • CERTIFIED EXPERT
  • 53,865 POSTS
Hello,

If the engine cooling system thermostat is stuck open it will not allow the engine to go into closed loop which holds the transmission out of overdrive. Lets run the codes which will confirm the issue. Here is a guide:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.

Cheers, Ken

Oct 29, 2018 at 10:40 AM