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View Full Version : 3 speed w/ over drive. Quick explanation please.



'66Commander
05-02-2013, 08:59 PM
So after searching and taling with many people about stick and over drive. I hav heard that OD makes it into a four speed: 1, 2, 3, OD. But I also heard that it makes it into a six speed: 1, 1w/OD, 2, 2w/OD, 3, 3w/OD.
Which of these are right?
And if I understand it right, the OD switches the ratio on the rear axle from 1:1 to 1:1.5 Drivetrain:tire roation.Do I have that right? If not, please explain.
Thank you all very much! :)

BobPalma
05-02-2013, 09:06 PM
First you have to define "speed."

If by speed you mean a different ratio of crankshaft revolutions to transmission output shaft revolutions, which is the usual definition of how many "speed" a transmission is, then using overdrive in combination with all three forward "speeds" does produce six different "speeds." (However, getting into first overdrive without a separate governor by-pass switch will have the engine screaming.)

Overdrive does not change the rear axle ratio; it has nothing to do with the rear axle or differential. It does change the ratio of transmission input shaft speed relative to output shaft speed. :) BP

duncan1951
05-02-2013, 09:07 PM
The overdrive (at least the electric triggered one in my Hawk) is able to kick in at speeds at or near 30 MPH. If you want to take first gear regular over 30 then you could let of the accelerator and it would shift to 1st OD, then shift to 2nd and you are in 2nd OD unless you floor it which will kick down to 2nd regular then let off and WaLa! 2d OD, same when you go to 3rd.
Normal driving (normal is relative) would be 1st, 2nd, 3rd then let off accelerator to go into 3rd OD. Of course if you are in a situation where cruising in 2nd is better due to speed limits or traffic you can always then let off and go into 2nd OD. Switching from OD back to regular in 2nd or 3rd (even 1st if you want to press it) is just like kicking a modern automatic down into passing gear except it will stay there until accelerator let off again and it goes back to OD.

Not sure of ratios but the Hawk at highway speeds in 3rd usually drops at least 500 RPM when OD is engaged.


WOW that turned out to be long winded!!:o

'66Commander
05-02-2013, 09:18 PM
My over drive is a chrome pull knob. Pulled is disengaged and pushed is engaged. I'm not really sure anything past that :/

BobPalma
05-02-2013, 09:23 PM
My over drive is a chrome pull knob. Pulled is disengaged and pushed is engaged. I'm not really sure anything past that :/

Ethan, it is more accurate to say that when the knob is pulled out, overdrive is not available to you and the transmission might as well be a straight three speed in all respects, including engine braking when decelerating.

When the knob is pushed in against the dash bracket, it means overdrive is available to you. It doesn't mean it is "in" overdrive, only that you have the option of engaging overdrive at will if the car is going fast enough. :D BP

'66Commander
05-02-2013, 09:31 PM
How does the overdrive work? Will it automatically enage when the knob is in?
How would I use it properly?

duncan1951
05-02-2013, 09:35 PM
How does the overdrive work? Will it automatically enage when the knob is in?
How would I use it properly?

Read my long winded post above #3

Mark57
05-02-2013, 09:41 PM
Head to the link attached below and you can read all about BW Overdrive Transmissions, straight from the "horses mouth" as it were. ;):)

http://www.tocmp.com/manuals/trans/Borg-Warner%20Overdrive/index.htm

duncan1951
05-02-2013, 09:45 PM
Head to the link attached below and you can read all about BW Overdrive Transmissions, straight from the "horses mouth" as it were. ;):)

http://www.tocmp.com/manuals/trans/Borg-Warner%20Overdrive/index.htm

OK, my post doesn't seem so long winded now by comparison :!!:

'66Commander
05-02-2013, 09:45 PM
Okay. Thank you. I must have loaded the page right before you posted. Haha.
So would I be albe to leave the knob pushed in?

'66Commander
05-02-2013, 09:46 PM
Awesome. Thank you!

tbirdtbird
05-02-2013, 09:49 PM
You are making it more complicated than it is.
Leave dash knob in at all times
(if you live in the mountains let us know so we can give you a slightly different take on this).
Shift thru the gears in the normal way 1-2-3. You are usually doing about 20-25 when you shift into 3rd.
When you get up to 30, momentarily let your foot off the gas pedal and it will automatically kick into OD, whereby engine speed drops way more than 500 rpm, it will drop 33 %, thus extending the life of your engine.
Yes, it is like having a 4th gear.
As stated above, you could theoretically have 1st in OD and 2nd in OD but you will have to rev the nuts off the engine to do this, which defeats the purpose of the OD sparing high engine rpm.
When you are slowing down or coasting to a slower speed, once you get below about 25-27 mph the OD will automatically drop out.
You never have to really do much of anything to make it work.
The Borg Warner engineers stayed up really late at night to come up with this marvelous invention. Necessity is the mother of invention. Automatic trannies had not yet been invented, so numerically high rear end ratios still prevailed. (automatics have numerically lower rear ends because they use a torque converter) and as roads improved, you could go faster esp in more remote areas. The OD gave you a way to go faster with the numerically high rear ends and not kill the motor.
I personally never use the kick-down feature, I don't like to rev the engine that much. Revs is what kills a motor, more than anything

OK we are all typing at once....!!

'66Commander
05-02-2013, 10:03 PM
I do live in a mountain area. So there are plenty of hills. But I won't be going into the mountains themselves. For a while at least.

tbirdtbird
05-02-2013, 10:22 PM
OK, depends on how mountainous it is!!!!!
I was hoping not to make this complicated.
If the knob is "In" then you will not be able to slow the car much by engine braking, which is the effect of the engine slowing the car when coasting.
This may not be a concern in the case of mild hills.
But if you have really steep hills to go down, or down hills with a really long way to go to get to level, you might miss that engine braking.
If this is the case, pull the lever out. This will negate all effects of the OD and you will have the usual engine braking. And of course no OD at all.
Now: I was taught by an old timer to NEVER push or pull the knob out while the car is under way at the risk of damaging the OD. So, I don't. Proceed at your own risk.

'66Commander
05-02-2013, 10:29 PM
Yeah I have heard that if I do push/pull the knob, pushing in the clutch at a light is the best way. Thank you very much :)
I'm also reading in the link above that overdrive (When under "cut in" point) that the free wheeling of the OD allowes you to shift gears without releasing the clutch. Does this mean I can shift gears under 30mph without pressing the clutch? That doesn't sound right...
(I'm reading page 7, lower right hand side of the page)

tbirdtbird
05-02-2013, 10:58 PM
Ya, that is wild, right !
Ya , if the knob is "In", you can shift without the clutch up to about 20 mph, but whenever i have done it there is always a slight amount of gear clash so I don't do it. And to get off the line from a dead stop you still have to use the clutch in the usual fashion.

'66Commander
05-02-2013, 11:02 PM
Ah that is crazy! They were ahead of their time!
I think I might just push in the clutch anyway.
But very cool none the less.

Dwain G.
05-02-2013, 11:10 PM
One of the first lessons in Level 1 Overdrive class is "Always put the shifter in reverse when you park'. Think of it as the 'P' position. If you do not learn to do this, the car will roll away someday. This is because of the 'freewheeling' feature when the OD cable is pushed in.

'66Commander
05-02-2013, 11:17 PM
Good advice. That last thing I want is to have it roll away.

duncan1951
05-02-2013, 11:27 PM
You are making it more complicated than it is.
Leave dash knob in at all times
(if you live in the mountains let us know so we can give you a slightly different take on this).
Shift thru the gears in the normal way 1-2-3. You are usually doing about 20-25 when you shift into 3rd.
When you get up to 30, momentarily let your foot off the gas pedal and it will automatically kick into OD, whereby engine speed drops way more than 500 rpm, it will drop 33 %, thus extending the life of your engine.
Yes, it is like having a 4th gear.
As stated above, you could theoretically have 1st in OD and 2nd in OD but you will have to rev the nuts off the engine to do this, which defeats the purpose of the OD sparing high engine rpm.
When you are slowing down or coasting to a slower speed, once you get below about 25-27 mph the OD will automatically drop out.
You never have to really do much of anything to make it work.
The Borg Warner engineers stayed up really late at night to come up with this marvelous invention. Necessity is the mother of invention. Automatic trannies had not yet been invented, so numerically high rear end ratios still prevailed. (automatics have numerically lower rear ends because they use a torque converter) and as roads improved, you could go faster esp in more remote areas. The OD gave you a way to go faster with the numerically high rear ends and not kill the motor.
I personally never use the kick-down feature, I don't like to rev the engine that much. Revs is what kills a motor, more than anything

OK we are all typing at once....!!

As I said, my Hawk at highway speeds drops RPM about 500 maybe 600 which is about 30% which is what Borg Wraner states as their OD reduction. If someone is getting 'way more' than that RPM reduction at highway speed they are doing good or running a lower (higher numericaly) rear end ratio. I was comparing 2100 rpm to say @ 1500 or about 30%. Not 4000 to 2800. Just my example on my particular Stude.

rockne10
05-03-2013, 12:00 AM
You are making it more complicated than it is.
Leave dash knob in at all times

Everyone has their favorite. If I am running around town, or even back and forth to work, I keep the overdrive locked out (cable pulled out) in straight three-speed. There's no way I am going to experience sufficient fuel savings to make it worthwhile to be free-wheeling. And that makes no difference if I'm climbing hills or coasting the plains. With overdrive locked out, I may even get three times the wear out of my brake pads, utilizing engine compression for braking.
I always lock out before cresting a hill or mountain. You CAN pull the cable out while you are in motion if you're drive is totally disengaged through the clutch.
I've never revved to the point where I could engage 1st over but, 2nd over is the cat's meow for entering interstate traffic. And, if I'm on the highway, until I'm about to crest that mountain, it's third-over, baby! CRUISE !
Best mileage I ever got was with a 289, 3-spd OD, 3.07 rear at 55 mph= 28 mpg.

duncan1951
05-03-2013, 12:12 AM
28 mpg with a Stude 289 - nothing to sneeze at for sure! Eat your heart out 40 HP Volkswagons :!!:

jackb
05-03-2013, 06:52 AM
agree with post #21.......spend a few bucks and get any Stude owners' manual and read the info on how a "new" owner is to use the OD. Its not rocket science. when all is right, drive it like the book says ...

tbirdtbird
05-03-2013, 06:59 AM
sorry Duncan, i didn't do the math! dave

duncan1951
05-03-2013, 07:53 AM
One of the first lessons in Level 1 Overdrive class is "Always put the shifter in reverse when you park'. Think of it as the 'P' position. If you do not learn to do this, the car will roll away someday. This is because of the 'freewheeling' feature when the OD cable is pushed in.

This was a learned habit for me - almost watched her roll a few times :eek:
also remembering that it is in reverse and not "showing off" and reaching through the window, turning the key and showing how it fires right up without assistance - the ole reverse two step :ohmy:

Commander Eddie
05-03-2013, 09:20 AM
This has been a very informative thread. I thought I knew all the little nuances of BW overdrive but it turns out this old dawg learned some new tricks here. This why the Studebaker Forum is so neat.

Ed Sallia
Dundee, OR

PackardV8
05-03-2013, 10:17 AM
As I said, my Hawk at highway speeds drops RPM about 500 maybe 600 which is about 30% which is what Borg Wraner states as their OD reduction. If someone is getting 'way more' than that RPM reduction at highway speed they are doing good or running a lower (higher numericaly) rear end ratio. I was comparing 2100 rpm to say @ 1500 or about 30%. Not 4000 to 2800. Just my example on my particular Stude.

Regardless of perception or recollection, it's simple math. Thirty percent overdrive is thirty percent reduction in the RPMs whatever the rear end ratio. With a T96 or T86 it will be 30% and with a T85/T89, the RPMs will drop 28%. The fuel mileage will not increase in that direct proportion, as frontal area, rolling resistance and vehicle weight are constants.

FWIW, I find the noise reduction to be as valuable to me as any fuel savings. Overdrive also reduces exhaust valve seat wear, as the valves are hitting the seats 30% fewer times on long highway trips.

jack vines

rusty nut garage
05-03-2013, 11:21 AM
This forum needs a well written sticky explaining the OD basics and how to drive them. I was surprised to learn that the majority of stude customers I have don't understand how to drive them or the necessary safeguards when parking.

dictator27
05-03-2013, 01:27 PM
Overdrive can be engaged or disengaged when the vehicle is in motion simply by flooring the accelerator. To be more accurate FREEWHEELING can be engaged or disengaged this way. If you are approaching a steeper downhill grade with the vehicle in od floor the accelerator. Doing this will kick the transmission out of od into normal three speed configuration. With the accelerator still held down, pull out the od dash control, then back off on the gas pedal. The car will now be in normal three speed mode, giving you engine braking capability. A word of caution here. Do this BEFORE you start down a steep downgrade! Ask me how I know.

If you are driving in normal three speed mode and want to engage the od while in motion, the procedure is the same. Floor the accelerator and with the pedal held down, push the knob in. If you are above 30 mph, the car will immediately go into od when you ease off on the loud pedal.

Hope this helps.

Terry

'66Commander
05-03-2013, 03:18 PM
Agreed, there needs to be a sticky post about this lol.
I thank you all for your help!
I'll keep checking for more. Can't have too much, eh?
Dictator27, I am curious how. I like stories.

jackb
05-03-2013, 03:28 PM
not wanting to argue....but, I never floor it to "engage" OD....simply push the OD handle in and the next time you let of the gas pedal at all, you should feel it kick into OD...

StudeRich
05-03-2013, 03:44 PM
not wanting to argue....but, I never floor it to "engage" OD....simply push the OD handle in and the next time you let of the gas pedal at all, you should feel it kick into OD...

That should work Jack, but please do not try taking it OUT of Overdrive without it being floored (in Direct), or bad things WILL happen. :(

And that is when you do need to shift it the most, when you are about to descend a Hill !

wagonairedriver
05-03-2013, 04:35 PM
I like second/ second O/D around town. Usually leave the knob in all the time. Learned about leaving it in reverse the hard way. Went into the house, came back out and NO CAR. He had "gone to see the neighbors" all by himself Just sitting on their front yard, by the door. Fortunately, it was after dark, so I quietly crept across their yard and retrieved the car, with no witnesses.

dictator27
05-03-2013, 05:02 PM
Dictator27, I am curious how. I like stories.

"63 Champ pickup 259 od. Mount Seymour Parkway in North Vancouver is several miles long, steep, narrow and has several switchbacks. There is only one road, so you come out the way you went in. I should have taken it out of od on the way in (up). The switchbacks keep speed down to less than 30 mph. I wasn't too far into the return trip when I started to feel the brake pedal getting hard. There isn't a long enough straight or flat stretch on that road to accelerate and take it out of od. Besides, there is just something about speeding up with an unguardrailed (?) switchback approaching at what seems like the speed of light! :eek: By the time I got to the bottom of the hill, I had a very hard brake pedal and a powerful smell of overheated brake linings. Oh, and a few more grey hairs. :( :ohmy:

Terry

LeoH
05-03-2013, 05:05 PM
You're welcome. I have an outlier example to share.

Someone has put in a cutoff switch bypassing the solenoid in my OD. The lever is always in and OD can be switched by the toggle switch under the dash.
We have learned already that, to get the car into reverse, the OD toggle needs to be 'off'. The mechanic, who had done this very thing on a couple of his Studes forgot about this kludge when he had the car and had a devil of a time trying to figure out why the car didn't go into reverse.

duncan1951
05-03-2013, 07:05 PM
I like second/ second O/D around town. Usually leave the knob in all the time. Learned about leaving it in reverse the hard way. Went into the house, came back out and NO CAR. He had "gone to see the neighbors" all by himself Just sitting on their front yard, by the door. Fortunately, it was after dark, so I quietly crept across their yard and retrieved the car, with no witnesses.

Not too scary but drove into the gas station filled up the Hawk right after getting it and went inside to buy some other items leaving it in a gear other than reverse. The lady beind the counter looked out and said where's that guy going? A simple wind had headed it off the pad and across the lot to snuggle up with the fence - I said " that's me, how do you like my 'new' car?" Whew!! :o no harm no foul
n

jackb
05-05-2013, 10:32 AM
yes to that Rich...I almost daily go in and out of OD using the accelerator correctly for the "out of OD" transfer..kind of like my 4WD...I put it in 4WD weekly....old habits..

brngarage
05-05-2013, 01:43 PM
Many years ago I had a '53 Commander w/overdrive and I installed an additional kick down switch under the dash (easily reachable) so I could disengage overdrive without flooring the throttle. Worked very well on long slow upgrades where I didn't want to "floor" it and even better if I encountered a surprise downgrade!

62champ
05-05-2013, 05:55 PM
Many years ago I had a '53 Commander w/overdrive and I installed an additional kick down switch under the dash (easily reachable) so I could disengage overdrive without flooring the throttle. Worked very well on long slow upgrades where I didn't want to "floor" it and even better if I encountered a surprise downgrade!

My Uncle had something similar to this only it did not allow the OD to kick-down. IIRC it was mounted just under the front edge of the seat - and seeing that the accelerator pedal was usually on the floor it was used quite a bit.

altair
06-03-2013, 01:59 AM
When I was 18 I had a 48 Dodge with a small V8 with OD and I drove it as a 5 speed. 1st conventional, 2nd conventional, 2nd OD, 3rd conventional then 3rd OD. This was achieved by a dash mounted press button that functioned the same as the "kick-down" with out flooring the accelerator. You had to be 18 to do this it was a bit trickey. Some early sports cars had a toggle switch mounted on the gear shift lever that allowed you to select OD electrically. My Rube Gold Berg idea was on the same principal. A small button with light wire through a relay to actuate the "kick-down" solenoid wired to the shift lever is very possible to duplicate this same system. To function in this manner the OD lever must be engaged, however it is possible to operate the engage/disengage lever elecrtically using a solenoid or a 4 wheel drive in-out motor assembly there endless possibilities Dave British Columbia ps I have seen cars roll away in gear where there is poor compression, one cylinder goes over centre and so on.