YACT: When to use Overdrive?

[BD2003]

Originally posted by: Fraggable
I almost posted the same question a few days ago.

In my (auto) Mustang, if I turn OD off it affects all 4 gears, so it's not like it's a 5th gear like I always thought. I've found that I get much smoother gear shifts and fewer downshifts if I turn it off below 40MPH.

I've never heard of such a thing. Overdrive is referring to a specific property of what is usually the highest gear (some high-end have more than one OD gear).

I could imagine that it would change the shift points of the gears, but disabling OD should in theory disable top gear - are you SURE it's shifting into 4th and youre not just feeling 3rd lockup?

 

[Fraggable]

Originally posted by: BD2003

Originally posted by: Fraggable
I almost posted the same question a few days ago.

In my (auto) Mustang, if I turn OD off it affects all 4 gears, so it's not like it's a 5th gear like I always thought. I've found that I get much smoother gear shifts and fewer downshifts if I turn it off below 40MPH.

I've never heard of such a thing. Overdrive is referring to a specific property of what is usually the highest gear (some high-end have more than one OD gear).

I could imagine that it would change the shift points of the gears, but disabling OD should in theory disable top gear - are you SURE it's shifting into 4th and youre not just feeling 3rd lockup?

No, I'm not sure exactly what it's doing, I haven't spent that much time with it yet, but it seems like it just causes higher RPMs all around when it's off. I'll try to figure out if it will go into 4th with OD off.

 

[tfinch2]

Originally posted by: TheGoodGuy
first off the over drive gear is a gear that is 'lower' ratio than the last gear.. like in sticks, your 5th gear would be considered over drive.. if you are on a 5 speed manual.

Anyway you use it at highway speeds (flat lands) to get better gas mileage, but dont try using it to climb hills and stuff, cause overdrive button back int eh day meant a seperate gear thinge, but yeah.. its good for highway only, dont try climbing steep hills with it, its not worth it, probbaly ruin your tranny.

:laugh:

 

[Scarpozzi]

If you use OD, your gas milage will improve, most-likely. What it will do is keep your engine from slowing your car when going down a hill....thus you won't be losing momentum through your engine/drivetrain and causing your RPMs to rise.

The adverse affects will be decreased acceleration, but that's only when you get to the upper gears anyhow. You can turn OD off when you want to get an extra boost to pass someone on the road or drive up a hill and keep your car from having to downshift frequently to compensate for high up-hill speeds.

 

[Minjin]

Originally posted by: BD2003

Originally posted by: Fraggable
I almost posted the same question a few days ago.

In my (auto) Mustang, if I turn OD off it affects all 4 gears, so it's not like it's a 5th gear like I always thought. I've found that I get much smoother gear shifts and fewer downshifts if I turn it off below 40MPH.

I've never heard of such a thing. Overdrive is referring to a specific property of what is usually the highest gear (some high-end have more than one OD gear).

I could imagine that it would change the shift points of the gears, but disabling OD should in theory disable top gear - are you SURE it's shifting into 4th and youre not just feeling 3rd lockup?

Such a thing DOES exist. I have one in my driveway. A Volvo 4 spd with push button overdrive. The tranny was designed as a 4 spd tranny in the 70s and it was updated with the overdrive tail section. When I'm in 4th, I push in the clutch, then push the button on the shifter, and a new final drive is engaged. If the gears were strong enough, I could technically do this at any time and I would effectively have 8 gears (there's a lockout to prevent this from happening). The Corvette 4+3 tranny is similar.

Mark

 

[imported_Phil]

Originally posted by: Fraggable

Originally posted by: BD2003

Originally posted by: Fraggable
I almost posted the same question a few days ago.

In my (auto) Mustang, if I turn OD off it affects all 4 gears, so it's not like it's a 5th gear like I always thought. I've found that I get much smoother gear shifts and fewer downshifts if I turn it off below 40MPH.

I've never heard of such a thing. Overdrive is referring to a specific property of what is usually the highest gear (some high-end have more than one OD gear).

I could imagine that it would change the shift points of the gears, but disabling OD should in theory disable top gear - are you SURE it's shifting into 4th and youre not just feeling 3rd lockup?

No, I'm not sure exactly what it's doing, I haven't spent that much time with it yet, but it seems like it just causes higher RPMs all around when it's off. I'll try to figure out if it will go into 4th with OD off.

Correct. Old MG-Bs used to have an overdrive unit, that, when engaged, would alter the ratio of 3rd and 4th gears (IIRC) by 1:1.25. That is the correct term for overdrive, but it has been used in recent years to describe a "top" gear.

 

[desy]

My buddy was was always using drive instead of OD in his explorer till I explained it to him. He was misinterpreting it just the opposite, that OD was the towing option.
Makes me wonder how many people do this and how much gas is being wasted because of it?

 

[BD2003]

Originally posted by: Minjin

Originally posted by: BD2003

Originally posted by: Fraggable
I almost posted the same question a few days ago.

In my (auto) Mustang, if I turn OD off it affects all 4 gears, so it's not like it's a 5th gear like I always thought. I've found that I get much smoother gear shifts and fewer downshifts if I turn it off below 40MPH.

I've never heard of such a thing. Overdrive is referring to a specific property of what is usually the highest gear (some high-end have more than one OD gear).

I could imagine that it would change the shift points of the gears, but disabling OD should in theory disable top gear - are you SURE it's shifting into 4th and youre not just feeling 3rd lockup?

Such a thing DOES exist. I have one in my driveway. A Volvo 4 spd with push button overdrive. The tranny was designed as a 4 spd tranny in the 70s and it was updated with the overdrive tail section. When I'm in 4th, I push in the clutch, then push the button on the shifter, and a new final drive is engaged. If the gears were strong enough, I could technically do this at any time and I would effectively have 8 gears (there's a lockout to prevent this from happening). The Corvette 4+3 tranny is similar.

Mark

Hmm, never heard of that, interesting stuff.

Pretty sure a mustang isn't designed like that though. Dropping it out of OD would definitely raise the revs - when I put my old neon in 3, it would wait longer before shifting even if the same amount of throttle was applied. And it still felt like there were 4 gears, just that the "4th" gear was it locking up in 3rd gear, which it otherwise doesn't do.

 

[PowerMacG5]

Originally posted by: Fraggable

Originally posted by: BD2003

Originally posted by: Fraggable
I almost posted the same question a few days ago.

In my (auto) Mustang, if I turn OD off it affects all 4 gears, so it's not like it's a 5th gear like I always thought. I've found that I get much smoother gear shifts and fewer downshifts if I turn it off below 40MPH.

I've never heard of such a thing. Overdrive is referring to a specific property of what is usually the highest gear (some high-end have more than one OD gear).

I could imagine that it would change the shift points of the gears, but disabling OD should in theory disable top gear - are you SURE it's shifting into 4th and youre not just feeling 3rd lockup?

No, I'm not sure exactly what it's doing, I haven't spent that much time with it yet, but it seems like it just causes higher RPMs all around when it's off. I'll try to figure out if it will go into 4th with OD off.

You might just be noticing the Torque Converter locking and unlocking. On my escape, I sometimes feel as if I have a fifth gear (even tho it is a 4 gear tranny), because when I am on a highway, and I push the gas in just a tiny bit for somemore go, the Torque Converter will unlock, allowing the engine to spin more in its power band, and then if I push it in a little more, the transmission will actually shift a gear.

 

[mercanucaribe]

I think a part of the problem is that a lot of cars show an "OD" light on the dashboard when you turn overdrive off.. And the button on the side of the shifter is labelled "OD". So people think that means OD is on.. then when they drive a car that has a lever position for OD, they assume that's the setting for towing etc.

 

[geecee]

Intel discontinued overdrive. So obviously you shouldn't use it anymore.

 

[DainBramaged]

This thread is so full of mis-information, it's quite amusing.

 

[Rudee]

Originally posted by: DainBramaged
This thread is so full of mis-information, it's quite amusing.

Totally.

 

[thomsbrain]

"overdrive," as it applies to your average detroit passenger car, is just your top gear (or gears, depending on the tranny). just put it in overdrive and let the transmission decide what gear it needs to get the job done. honestly, i've neverunderstood why american car companies think having the top gear below 1:1 was such an amazing feature that they have to completely change the way they label their autos, even if it doesn't change the way the driver should operate them at all. all they do is confuse people. just get a fvcking clue from the japanese, and label the autos D321.

regarding fraggable's mustang, all he is noticing is changing shift mapping when he turns it off. it's probably holding each gear longer. my accord will do the same thing when you put it in sport mode, except it will still use top gear when it needs it. it's actually very good for sport driving, because it grabs the next lowest gear just before you need it for corner exits, getting rid of the kickdown reaction time when you put your foot into it.

 

[imported_Phil]

Originally posted by: DainBramaged
This thread is so full of mis-information, it's quite amusing.

I wonder how many people here have actually seen an actual inline overdrive unit and know how it works?

 

[Fraggable]

Originally posted by: Fraggable

Originally posted by: BD2003

Originally posted by: Fraggable
I almost posted the same question a few days ago.

In my (auto) Mustang, if I turn OD off it affects all 4 gears, so it's not like it's a 5th gear like I always thought. I've found that I get much smoother gear shifts and fewer downshifts if I turn it off below 40MPH.

I've never heard of such a thing. Overdrive is referring to a specific property of what is usually the highest gear (some high-end have more than one OD gear).

I could imagine that it would change the shift points of the gears, but disabling OD should in theory disable top gear - are you SURE it's shifting into 4th and youre not just feeling 3rd lockup?

No, I'm not sure exactly what it's doing, I haven't spent that much time with it yet, but it seems like it just causes higher RPMs all around when it's off. I'll try to figure out if it will go into 4th with OD off.

I played with it on the way from work to school today, and it seems that the 4th gear just is not accessible with OD off, or you have to go faster than 65MPH on flat to get to it. It definitely does affect when it shifts into 2nd and 3rd though. I think it goes into both earlier.

 

[Juno]

i have a question on overdrive. i drive a '04 nissan xterra and it has an OD button. what will i have to enable OD? i'm still a bit confused about OD...

 

[OrganizedChaos]

Originally posted by: jagec

Originally posted by: allanon1965
"first off the over drive gear is a gear that is 'lower' ratio than the last gear.. like in sticks, your 5th gear would be considered over drive.. if you are on a 5 speed manual. "


Not true, while overdrive is a gear lower than the last, many 5 speeds are not overdrive, over drive is a ratio of approximatley .8 to 1 where drive is always a 1 to 1 ratio. many 5 speeds have a 5th gear which is a 1 to 1 ratio. some of course do not, but to say that a 5 speed is an overdrive is wrong...

Overdrive is ANY ratio lower than 1:1.

Originally posted by: TheGoodGuy
Anyway you use it at highway speeds (flat lands) to get better gas mileage, but dont try using it to climb hills and stuff, cause overdrive button back int eh day meant a seperate gear thinge, but yeah.. its good for highway only, dont try climbing steep hills with it, its not worth it, probbaly ruin your tranny.

How on earth would it damage your tranny? Explain this to me.

some transmissions can't handle alot of toorque in a small gear, i think the NV4500 comes to mind but that a manual.

 

[feralkid]

Originally posted by: Phil

Originally posted by: DainBramaged
This thread is so full of mis-information, it's quite amusing.

I wonder how many people here have actually seen an actual inline overdrive unit and know how it works?

I have a 1967 Triumph TR-4A with a Laycock De Normanville overdrive.

Effectively 7 forward gear ratios.

Ist is locked out, since it shares a layshaft with reverse, and engaging overdrive in reverse gear would instantly destroy the unit.

Old School stuff, for sure.

 

[DaTT]

Originally posted by: Juno
i have a question on overdrive. i drive a '04 nissan xterra and it has an OD button. what will i have to enable OD? i'm still a bit confused about OD...

Whats to be confused about?....its just another gear.

 

[feralkid]

Originally posted by: DaTT

Originally posted by: Juno
i have a question on overdrive. i drive a '04 nissan xterra and it has an OD button. what will i have to enable OD? i'm still a bit confused about OD...

Whats to be confused about?....its just another gear.

Let me guess...you haven't read any of this, have you?

 

[BD2003]

Originally posted by: feralkid

Originally posted by: DaTT

Originally posted by: Juno
i have a question on overdrive. i drive a '04 nissan xterra and it has an OD button. what will i have to enable OD? i'm still a bit confused about OD...

Whats to be confused about?....its just another gear.

Let me guess...you haven't read any of this, have you?

But it IS just another gear....

 

[archcommus]

Just fvcking Wiki it, sheesh.

 

[MercenaryForHire]

Originally posted by: allanon1965
many 5 speeds have a 5th gear which is a 1 to 1 ratio.

Every 5-speed I've seen has had a 1:1 fourth gear, and a fifth generally around ~0.7:1.

oh, and bandwagon-:laugh: +1 at TGG's incompetence.

- M4H

 

[feralkid]

Originally posted by: BD2003

Originally posted by: feralkid

Originally posted by: DaTT

Originally posted by: Juno
i have a question on overdrive. i drive a '04 nissan xterra and it has an OD button. what will i have to enable OD? i'm still a bit confused about OD...

Whats to be confused about?....its just another gear.

Let me guess...you haven't read any of this, have you?

But it IS just another gear....

Google is your friend.