When to use Overdrive?

[Dan Murphy]

You are correct, Charade, always keep in OD except in special circumstances, some of which you listed.

 

[Charade]

Interesting thread. I've been wondering about it myself. There was a thread on here a couple weeks about OD. Got me wondering. I have a button to turn it on or off. Now I know why in the past I'd try to pass a car and it took forever, if I was lucky enough to not have someone zip in the space I had any way. Only recently I've started turning OD off when I'm passing on the highway. Wow! Does it zip along! Definitely an improvement. But that's the only time I turn it off.

There is really no difference between what you did and just stepping on the gas pedal harder to the point the transmission downshifts to third on it's own. Pressing the OD button off just gives you a little more control when that will occur without the possible jolt from the engine revving up.

 

[SamNlikeSalmonbuthuman]

I've been driving my 98 Taurus in OD the entire time I've had it and right now it's not running so well. It started giving me trouble when I was driving through the mountain pass up a steep grade in cruise control going about 70mph. It still holds oil and water but sounds like it's on it's last legs. I'm afraid to drive it in D now but I think I'll give it a try in the city and see if it runs any better.

 

[lynxstch]

I've been driving my 98 Taurus in OD the entire time I've had it and right now it's not running so well. It started giving me trouble when I was driving through the mountain pass up a steep grade in cruise control going about 70mph. It still holds oil and water but sounds like it's on it's last legs. I'm afraid to drive it in D now but I think I'll give it a try in the city and see if it runs any better.

And you managed to find, and bump a 14 year old thread as your first post on a Disney board? Welcome to the DIS!

 

[SamNlikeSalmonbuthuman]

Thanks for the welcome! So I drove it in D around the city and it ran much better than it has been. There were a couple places I went where the speed went up to 55mph so when that happened I shifted it into OD until I got back to the 35mph zones. I was really surprised at how much better it drove not being in OD.

 

[tvguy]

And you managed to find, and bump a 14 year old thread as your first post on a Disney board? Welcome to the DIS!

And the information is just as current as it was 14 years ago.

 

[bcla]

Thanks for the welcome! So I drove it in D around the city and it ran much better than it has been. There were a couple places I went where the speed went up to 55mph so when that happened I shifted it into OD until I got back to the 35mph zones. I was really surprised at how much better it drove not being in OD.

Well yeah. Reviewing this old topic, it sounds like a lot of people know little about their vehicles. Overdrive just describes any gear where there's less than a 1:1 gear ratio. It's generally perfect for cruising at highway speeds. But in city driving an automatic transmission will just hunt for the right gear and will often just settle on the highest gear even though it's not the greatest.

But today there are a lot more continuously variable transmissions where the transmission just finds a spot. I know many have pseudo gear settings where one can choose "gears", but it kind of just places it near where a fixed gear would have been but can still vary the gear ratio a little bit.

I drive a manual transmission car and get a little bit of a different feel. One has to be more in tune with what the car really needs. If I was in top gear at low speeds I can feel it. An automatic transmission might actually run at top gear cruising at 35 MPH on a main thoroughfare, but the engine is somewhat lugging. That's really done more for better fuel economy than anything else.

 

[bcla]

And the information is just as current as it was 14 years ago.

There are a lot more CVTs there days then there were 14 years ago. Back then the I only one I remember was the Honda Civic HX. Now some carmakers have the bulk of automatic transmissions as CVTs. I think Subaru only has CVT automatics now except maybe for the BRZ automatic.

As for "overdrive", that still where the gear ratio is less than 1. I've heard of some cars where there are two gears which are overdrive. For example, here's the gear ratios in a 2018 Ford Taurus:

First Gear Ratio: 4.48
Second Gear Ratio: 2.87
Third Gear Ratio : 1.84
Fourth Gear Ratio: 1.41
Fifth Gear Ratio : 1.00
Sixth Gear Ratio: 0.74
Reverse Ratio: 2.88​

The only overdrive gear is 6th.

 

[tvguy]

There are a lot more CVTs there days then there were 14 years ago. Back then the I only one I remember was the Honda Civic HX. Now some carmakers have the bulk of automatic transmissions as CVTs. I think Subaru only has CVT automatics now except maybe for the BRZ automatic.

As for "overdrive", that still where the gear ratio is less than 1. I've heard of some cars where there are two gears which are overdrive. For example, here's the gear ratios in a 2018 Ford Taurus:

First Gear Ratio: 4.48
Second Gear Ratio: 2.87
Third Gear Ratio : 1.84
Fourth Gear Ratio: 1.41
Fifth Gear Ratio : 1.00
Sixth Gear Ratio: 0.74
Reverse Ratio: 2.88​

The only overdrive gear is 6th.

Those appear to me the exact same gear ratios as in my 2018 Ford Flex, probably the same transmission. But it goes into 6th just above 40 mph under normal operating conditions. The computer controls it all, so it shifts up and down a lot........a whole lot more than the 3 speed automatic in the 1987 Suburban I traded in.

 

[bcla]

Those appear to me the exact same gear ratios as in my 2018 Ford Flex, probably the same transmission. But it goes into 6th just above 40 mph under normal operating conditions. The computer controls it all, so it shifts up and down a lot........a whole lot more than the 3 speed automatic in the 1987 Suburban I traded in.

I can actually feel a car I drive (a Honda) go into 4th/top gear just cruising on a city street at 35 before I get to a light. This doesn't have a gear indicator, although I'm not sure what cars do these days. This one is like every Honda automatic I've seen for years with a light up display to indicate the shift selection, which includes P/R/D/D3/2. But I can play around with it and put it into D3 and see the revs rise. But year I can of course tell what gear it's in by looking at the speedometer and tach. I also remember an older car where it would hunt between 4th and 3rd when going up certain inclines. The usual solution was to put it in D3 so it didn't keep on shifting between gears. But the newer computer controlled transmission are much better at not unnecessarily changing gears.

It's really weird too as I've test-driven a few newer manual transmission cars, and some of them even have gear indicators on the instrument cluster.

 

[jec6613]

Gear hunting, at least on the latest Ford 6 speed, is basically a thing of the past, and hasn't damaged the transmission in pretty much anything since the mid 1990's - so long as it's a computerized transmission, it can hunt all day. It used to overheat and chew up the transmission bands, but the modern computers carefully monitor temperature so you don't need to worry about it.

The term, "Overdrive," is pretty well outdated in most passenger vehicles today, but it did used to mean gear ratios lower than 1.00, while Drive would be 1.00 exactly and bypass the transmission to reduce wear on it. However, that used to refer to the gear handling going out to the final drive, where on today's modern vehicles with FWD and AWD, the final drive and transmission are integrated into a single unit with no distinct final drive at all, so the numbers are essentially made up with even the highest gear is usually 3.20 or so to the wheels. Some trucks and of course the Ford Mustang and such still do have a final drive and so the term is still somewhat relevant, but not nearly as much as it used to be and not in any normal passenger vehicle.

The TL;DR is that you should just leave any modern automatic transmission vehicle in whatever the highest drive mode is and forget about it, unless you want to do something fancy like engine braking or an ice start.

Lastly, an earlier poster suggested that putting the vehicle in "1" would restrict it to first gear. This is a common misconception caused by not reading your vehicle's manual. But it's incorrect, it restricts it to first and second gear, usually using a high rev programming. In many AWD vehicles, including older Ford Escape and Subaru vehicles, it will also fully engage the rear wheels with a hard 50/50 power split. It's used to get a vehicle unstuck in deep sand and/or water, and also to provide heavy engine braking in the event your main hydraulic brakes fail or are insufficient.

The "2" position does indeed lock the vehicle into second gear, and it used to start on snow/ice where first gear would have too much torque to skip the gear. This is especially important since in an automatic transmission vehicle the starting torque coming out of the transmission is double what it is on a manual transmission vehicle.

 

[Squirlz]

There is so much wrong in that last post that I'm not even going to start.

 

[georgina]

I can actually feel a car I drive (a Honda) go into 4th/top gear just cruising on a city street at 35 before I get to a light. This doesn't have a gear indicator, although I'm not sure what cars do these days. This one is like every Honda automatic I've seen for years with a light up display to indicate the shift selection, which includes P/R/D/D3/2. But I can play around with it and put it into D3 and see the revs rise. But year I can of course tell what gear it's in by looking at the speedometer and tach. I also remember an older car where it would hunt between 4th and 3rd when going up certain inclines. The usual solution was to put it in D3 so it didn't keep on shifting between gears. But the newer computer controlled transmission are much better at not unnecessarily changing gears.

It's really weird too as I've test-driven a few newer manual transmission cars, and some of them even have gear indicators on the instrument cluster.

My 2011 manual Subaru Outback has a gear indicator to tell me what gear I am in!