Intermittent Trans Issues

[mrdtrx300]

I Have 2005 Aveo Lt with automatic transmission. When I drive the car and it warms up occasionally it won't shift into overdrive. So as I'm cruising down the interstate, I shift the car into neutral and key off and back on and put it into drive the car shifts into overdrive fine. I have no hold light or check engine light on. Have had a lost signal to Tcm before any insight is appreciated.

[avguy]

Have you checked the level and quality of the fluid? That's always the first step in diagnosing any transmission issue.

Beyond that, from prior threads, I'm aware of 2 issues which have caused various A/T problems.

First is ground issues, in particular the ground which is located under the battery tray.

The other one is corrosion in a transmission connector. So it would be a good step to undo and clean the TCU connector, along with checking all of the wiring going into it.

[mrdtrx300]

Have you checked the level and quality of the fluid? That's always the first step in diagnosing any transmission issue.

Beyond that, from prior threads, I'm aware of 2 issues which have caused various A/T problems.

First is ground issues, in particular the ground which is located under the battery tray.

The other one is corrosion in a transmission connector. So it would be a good step to undo and clean the TCU connector, along with checking all of the wiring going into it.

I haven't driven the car enough to give a definitive answer yet. I did clean the ground you mentioned and all seems well so far. Just need to log a few more miles to know for sure. I appreciate you input.