Overdrive?

[jsbihn]

Thanks HT for the clarification and thank you to everyone for the info.

3 gears plus over drive...... yep that explains the crappy gas mileage.

So the next question is there a way to swap the overdrive unit out and modify it?
Or is it internal with the trans (meaning it is not a separate unit).

Just wondering HT, is there a better trans that could swap out with the 4L65e to give 1) better gas mileage 2) extra gears
I know they did the later models with the 4L60 (right?) and it has 5-6 gears but I also heard that swapping that in would be expensive and a nightmare that as it was stated "you would be half way to a diesel conversion"