What exactly is the OD button for?

[Turdle]

I guess I really do not get how OD works! If its nothing more then a 4th (or 5th) gear, Then why is it if I am in 1st or 2nd gear and hit the OD off button, The rpm's change?

My truck doesn't do this

one of the things it does is locks up the torque converter, helps you out with engine breaking a little.

The OD has nothing to do with the torque converter lockup. I can feel mine lock with "OD off" light illuminated, or dark.


Glacier, I hope you see this thread--

 

[JIGAWHAAT]

My truck doesn't do this

I am at least 90% sure mine does anyway. I gotta run out for some beer soon. I will double check it then.

 

[cgriffin_5139]

I use that button everyday for those 2 reasons. I tow often, also there are alot of hills in my area and like you said those long steep ones are when I turn the OD off. I also turn it off when I am off road. I dont know if I should or not. But it does not make sense to me to be in OD off road. Am I correct?
JIGA

oh yeah that is true i forgot about that

 

[cgriffin_5139]

I am at least 90% sure mine does anyway. I gotta run out for some beer soon. I will double check it then.

Get a 40 of old E, yeah the packy closes soon!

 

[JIGAWHAAT]

I am at least 90% sure mine does anyway. I gotta run out for some beer soon. I will double check it then.

Well I just took her for a blast down the road and well shocker.. I was wrong. I do'nt know why I thought it did that but it does not.
Not the first time I have been wrong, And it wont be the last. That I promise!
JIGA

 

[JIGAWHAAT]

Get a 40 of old E, yeah the packy closes soon!

Packy does'nt close till 9 pm here. 11 pm ten min. up the road in MASS

 

[Turdle]

My truck doesn't even attempt an OD upshift until 40 MPH.

Around that speed though--it is in and out of OD.

 

[AERBROCONVIL]

The od removes od... for towing. no top gear upshift at cruising speeds. This removes overdrive, which is prone to slippage when extra weight, or hilly terrain is encountered.

 

[K80]

See how it all works

http://auto.howstuffworks.com/automatic-transmission3.htm

 

[coaxxx]

my overdrive just went out...meaning it doesnt work. the light is out and it canot be switched off (light on). is this ok for the life of my truck? im assuming it would be a pain to fix. i do tow my quad a couple times a year.

 

[TheJackal]

my overdrive just went out...meaning it doesnt work. the light is out and it canot be switched off (light on). is this ok for the life of my truck? im assuming it would be a pain to fix. i do tow my quad a couple times a year.

If the light is on and you can't turn it off, it means there's something wrong with the transmission. Have it looked at soon.

 

[rwenzing]

The Transmission Control Switch (AKA the O/D Button) is driver controlled and it toggles between the O/D ON and O/D OFF modes. The key-on default mode is always O/D ON and it provides maximum fuel economy.

Using the 5R55E as an example

O/D OFF mode does 2 things when the shift lever is in the drive position:

• It locks out 5th gear, allowing the PCM to select gears 1 through 4 only;
• It applies the coast clutch in 4th gear to provide engine braking.

O/D OFF mode has 2 primary uses:

• To eliminate shift hunting between 4th and 5th gear;
• To provide engine braking in 4th gear.

 

[Redtrac01]

I turn mine off when going down the steep hills near me to use engine breaking. I don't have to ride the brakes that way and it works quite well. I also turn it off when towing my boat. I've often wondered if it puts more wear on the transmission to use it as an engine break, but it still works fine after 120K miles.

 

[Donner]

Still confused...

thats truth.

is no 5th gear.5th gear if i'm not mistaken is 2 and 3 together and is used to lower your rpm for highway speeds.

hope i help

OD is on by default... you have to hit the button to turn it off. Why would you have to turn it off every time you started driving? Wouldn't it be the other way around since most of us drive on paved roads?

 

[Donner]

See above...

A transmission mechanic once told me that for city driving you should keep your O/D off because you'll end up wearing out your trans with it on. Reason is that on city streets you're constantly 'stop and go' so when your trans kicks into 4th and then drops right back repeatedly, it's actually bad on the trans. Plus he said that would cause it to heat up more. He said 4th gear isn't really a power gear, but a "cruising" gear for highways to lower your RPMs and give you better MPG. So having your trans kick into 4th over and over is bad for it. That's one of the big causes for trans failure, according to him, especially if there's a load on the vehicle.

How is this so? Keeping the OD off?

 

[FROADER]

I don't shift into OD until about 60. I never use it around town.

 

[Donner]

Vehicle is a stick?

I don't shift into OD until about 60. I never use it around town.

So you have to engage the OD in a manual? I don't remember my 96 OD

 

[FROADER]

Yeah, 1st gens have the P R N OD D 2 1.

 

[Donner]

Ford took that option away...

Yeah, 1st gens have the P R N OD D 2 1.

Wow! You took a pic driving at 80? and w/a cell phone? Very brave!

So now OD is recommended, but it wasn't before... that's confusing.

 

[storlied]

This thread got me pretty confused.

So is there any bad in turning OD off for engine braking? Say coming from 50mph.
I keep it on 98% of the time, no matter where I'm at, or what I'm on.
So going uphill, it's better to take OD off so you're not putting so much stress on the engine/tranny?