To Overdrive or Not To Overdrive

[DrewsCam]

To begin with i really dont no what overdrive does, the dealer just said to always drive with it cause it saves gas

What actually does it do, and do you drive with it on or off?

When i do turn it off the engine slows down, you can definetly feel a power decrease

[PtBaller]

Overdrive is just 4th gear. When o/d is off the car doesn't shift to fourth.

[Redline]

using overdrive is giving you that last gear (4th)...otherwise, you'd be driving around with only 3 gears. The reason you feel the "power decrease" is b/c if you were originally on 4th gear, when you take O/D off, the car drops to 3rd gear and the speed will change b/c you can only run so high a gear velocity on a certain set.

It only saves gas for highway/constant speed driving. If you take the RPMs over a certain level (say 4000RPM), then the engine eats gas. Most likely you'd go over that level in highway driving if you were stuck in 3rd gear. Also, I read it changes the shift points designated by the comp....unless thats the ECT (someone correct me if I'm wrong)

[SuperSolara]

Some of the early ECT (electronically controlled transmission) had a normal and power mode which would vary slightly the shift points. This was done away with in later cars because it really did nothing to make the car accellerate faster since even in normal mode it would stay in lower gears until redline if you gas pedal was floored. Gear ratios stayed the same of course.

[Nick]

not again with this, please do a search, we've been through this so many times