Anyone know how over drive works.The rx-8 has it right if i member. So when would u use over-drive.

Works quite nicely, thank you.

An overdrive gear is any gear with a ratio less than one. Most if not all cars now have overdrive, it is mostly used for fuel economy, i.e. highway cruising. For the RX-8, 6th gear is the overdrive since 5th gear is 1:1 ratio. Am I right?

i thought theres a over button ?

Nah. neit_jnf is correct (& 5th isn't overdrive).

no no i mean isnt there a over drive button?

Originally posted by Dookie_Rx-8
no no i mean isnt there a over drive button?

Not on the 6 speed. Don't know about the AT, however.

Originally posted by Dookie_Rx-8
no no i mean isnt there a over drive button?

Not on the A/T.

On the automatic, your 4th gear IS your overdrive gear. It is tuned to 0.694.

So why is there a button for it on some cars? Why would you want to turn it off?

The main reason for offering the O/D off function on most AT cars is to allow the driver to cruise on local road on a higher gear ration so that car a little bit more responsive to the throttle position.

On most modern cars with an "O/D Off" button, it simply prevents the transmission from dropping into the top gear. This can be useful around town, because it can provide a little sharper throttle response in traffic.

On some older (particularly British) cars, an electric overdrive was an optional accessory. This unit mounted to the rear of the gearbox, and a shortened tailshaft was used to take the output from the rear of this extra unit. While intended only for use when in top gear, it could actually be engaged in any gear, and was thus popular amongst Land Rover enthusiasts because it gave them an extra four gear ratios to choose from while they were mud-bashing.