So confused over drive of drive

[Magichat]

Ive heard it doesnt matter ive heard drive is faster but which is it people.

I know od is better gas mileage but were talking speed

and what if your going 105 in D do you have to put it in OD?

[Jerriko]

OD is always better at 105. It depends on what you are doing and what trans you have. Non-electric vs electric seems to be the difference.

[Magichat]

electric tranny was introduced in 1994 i belive there for i have a 1996 which is a electric tranny

its conttolled by the PCM

[chas]

overdrive is a higher gear ratio. also the overdrive portion of most transmissions is usually the weakest. this is fine since the overdrive unit typically is used for cruising at highway speeds.

driving in D also delays t/c lockup until 70ish (or so i have read).

[98Camaro3.8]

Overdrive is simply 4th gear. That gear has a ratio higher than 1:1 (lower number). It's just like 5th gear in a manual. You can run in 3rd gear fine, but you can't go as fast because of the shorter ratio. D allows the tranny to shift between 1st and 3rd gears, but will stay out of 4th. OD allows it to go into 4th gear.
At the track, it doesn't matter if you're in D or OD. The tranny doesn't shift at WOT until near redline. You won't be going fast enough for it to need to shift to 4th.