Quote Originally Posted by ontarian_frog
You still don't get the meaning of overdrive. Unfortunately, you still don't understand the way the transmission functions.
I think I do. Fourth gear, in effect is 'overdrive', whether they call it that or not. There is no higher gear; it's a four speed. An automatic transmission is not fully (or solidly) 'in gear' until the torque converter locks up. That's the way a fluid drive torque converter works. But on an Aveo it doesn't lock up until 45 MPH. On most other cars it will lock up sooner, more like at about 40 or so.

So what about that do I not understand?