3 speed overdrive!!, now about getting it in.......

[BluTrukker]

Thats the info I have been looking for. Thanks so much. So if it draws 20amps, a relay that can handle 25 or 30 amps should be sufficient?

[slorio]

Yes. 30 amp relay is what I am planning. You can find an original wiring diagram and revised one to bypass the governor here:

http://www.classictruckshop.com/club...over/drive.htm

I hope this is helpful.
Regards,
Steve
New Orleans

[murdoc]

Hey to all who might be interested, I found a great chapter on these overdrive transmissions in an old hot rod book from 1968. It has some great info and wonderful pics of how to disassemble and reassemble the muncie version of these overdrives (the nonsyncronized ones). I know how hard info on these can be to get. I think it has better schematics than the current pdf files that are readily available online.

If any of you are interested in getting it, I have it scanned, send me a pm and ill email it your way.

The best of luck my friends, we who dabble with these nostalgic, innovative pieces of automotive history; we know we need it!

[slorio]

Just thought I would post an update. The overdrive transmission is now in my 1966 GMC behind my 305 V6. The results are sweet. Overdrive kicks in automatically after 30MPH. Gives a .70 to 1 ratio that is ideal for cruising at highway speeds. I think the old V6 is really going to love it.

If you follow this thread, UPS was kind enough to smash the governor in shipment and wouldn't honor the shipping insurance. Shipping insurance is a rip off. I ended up finding a new governor on E Bay, but it was 1.25" diameter threads for the early transmissions vs. mine with 7/8" threads for the later synchro transmission. Fortunately, I have a machine shop in the family and a nephew that was kind enough to cut and rethread the governor I bought.

These transmissions are a great way to get a cruising gear in our old trucks.
Regards,
Steve
New Orleans

[ol Curt]

Originally Posted by 1restorick

Sir, I have this transmission in my 1963 truck and it looks identical to yours. My column shift linkage is stock. This transmission works real nice, however my first gear is still non-sychromesh. The overdrive feature is awesome and with a 4:11 rear gear, I only spin 2000 rpm at sixty miles per hour. Best of luck in the install. It should be very straight forward. You will need a heavy duty relay and a gas pedal switch for the kickdown feature. Building a wiring harness for this installation is very straight forward.

Rick

I am interested in finding one of these and installing in my 66 C10. Can you provide info as where to look for them and what to look for in terms of their condition?

Thanks

[70 Suburban]

i to would like to know about what to look for. I have a 3 speed on the tree colomn on stanby just for this

[jsmithbm]

Bump.........
Dumb question, how can i tell if my 70 has a saginaw or munice 3 speed

[gochoa]

Originally Posted by BluTrukker

Thats the info I have been looking for. Thanks so much. So if it draws 20amps, a relay that can handle 25 or 30 amps should be sufficient?

Blutrukker,

did you wire your Sagina 3 speed with o/d, bypassing the the kickswitch and governor...have any pics or diagram. just my hands on one and no clue of how to wire it...thanks in advance.

[wutnxt]

This is all great information......

I have a 1966 fleet side big window long box custom truck with a 327 in it that has the original overdrive and a power booster set up in it that i was kind of wondering how rare or what to do with it. I just haven't got that far with it yet...it's what i would say is in the " line up for a build " thats a nice way of saying it's sitting in my field. I have already learned way more about that overdrive then i knew before great thread...

[Gianyveedub]

I just finished installing one of these in my truck yesterday by myself...man it is not easy holding these up with only one person. In regards to the bypass switch, what I have been wiring tonight is a relay going to the solenoid and using the governor as the ground for a relay with a on/off push button switch between the switched hot for the relay. That way I can turn on/off the OD when I want above 28mph and it will automatically turn the OD off when I slow below 28 mph so I don't accidentally take off in OD from a stop. I made a quick drawing of it:

Let me know what you think

[gochoa]

Gianyveedub,

Thanks for the reply. I know what you mean, I use as many jacks as I can,,LOL. That is exactly what I want to do with mine. What type of relay did you use? Can I get a pictures of how you have it wired. I'm a "visual" kind of man...in other words, can't comprehend wiring for S***. You can send them private message.

[Gianyveedub]

Once I have it finished I'll send the pics. Today was family day and I was not able to touch my truck at all...

[NCD1966]

i'm glad you guys gave this old thread some new life. I too have a 7 bolt 3 speed w/OD. and was looking at for the gear ratio for the OD. So people said it had a .85 and some say .70

Looks like I have one with .70.

anyone know how much horsepower they can handle?

[Gianyveedub]

Here is my unfinished wiring of the overdrive


Here is a series of pictures that I took trying to explain how it will work. I have not been able to finish it like I would like today, but life happens.

My color code is as follows:
-Yellow from Ignition to on/off switch to light to relay (#85)
-Red is from batt (fuse 20 amp) to relay (#30)
-Black is Ground/Governor to (#86)
-Green is Solenoid to relay (#87)

This one is of the whole setup. I am wiring a light between the on/off push button switch and the relay as you can see in the second photo.



The second is a close up of the on/off and light.



The third one is showing the batt wire with a fuse.



The fourth is of the Governor/Ground Wire



The fifth is of the solenoid wire



These last two are of the relay socket and the relay itself. It is a bosh relay 30amps.






In regards to ratio, it is a .70:1 ratio. The trans is a Saginaw and I would expect that like anything that is well taken care of, it should handle quite a bit. Not 500 hp, but a small block should do fine. They used to put these things behind 283's.

[murdoc]

Gianyveedub:

Excellent job man!! Im glad to see someones finally posted a wiring setup for these overdrives. Keep us posted on how this wiring goes for you.

[NCD1966]

Originally Posted by Gianyveedub

In regards to ratio, it is a .70:1 ratio. The trans is a Saginaw and I would expect that like anything that is well taken care of, it should handle quite a bit. Not 500 hp, but a small block should do fine. They used to put these things behind 283's.

Thanks on confirming the ratio. The reason Im asking about the power is because I have a 355 sbc that will has around 375hp and 400 lb of tq. I will be just crusing the truck. I not planning on running the truck real hard or any doing wide open shifting.

[kieth]

I did not look at the above relay wiring job, he wired it the way he wanted to, the instruction below are for a relay that comes prewired. Kieth

You will find the relay which is shown above with the plastic cap already prewired. I use them all the time.

1. The Blue wire is the supply for the 12 volt power to the relay.( Hot all the time)

2. The yellow wire is the supply of 12 volt power when you activate the relay

3. The Red center wire is not normally used but it supplies 12 volt power when the relay is not activated

4. The black wire is the ground for the relay (used here cleverly to only activate the OD when it is in the correct range of speed. )

5. The white wire is the trigger wire (activates the relay and sends power to the yellow)--controled here by a switch with a light that shows it is engaged)

They are really simple but when you look at them for the first time it gets really confusing ........Kieth

Only question I have is when you slow down does it automaticly downshift out of OD ?

here is a link to the prewired relay and how it is set up.



http://kieth.smugmug.com/Trucks/66-G...916151_PDBdGJX

[joedoh]

could you use a pair of relays and tap into the brake wire as a latching input, so that when you tap the brake the overdrive disengages? if the brake wire isnt the desired input you could put a brake switch on the clutch pedal and do the same thing. I can help you design that circuit if needed.

Originally Posted by kieth

I did not look at the above relay wiring job, he wired it the way he wanted to, the instruction below are for a relay that comes prewired. Kieth

You will find the relay which is shown above with the plastic cap already prewired. I use them all the time.

1. The Blue wire is the supply for the 12 volt power to the relay.( Hot all the time)

2. The yellow wire is the supply of 12 volt power when you activate the relay

3. The Red center wire is not normally used but it supplies 12 volt power when the relay is not activated

4. The black wire is the ground for the relay (used here cleverly to only activate the OD when it is in the correct range of speed. )

5. The white wire is the trigger wire (activates the relay and sends power to the yellow)--controled here by a switch with a light that shows it is engaged)

They are really simple but when you look at them for the first time it gets really confusing ........Kieth

a relay is a low current to high current switch, it doesnt need a "ground" and no pin is required to have 12v "hot all the time"

looking at the bottom of a relay there are 3 vertical pins and two horizontal pins. the two outside vertical pins (85 and 86) are the low current switch, you can feed ground or voltage to either pin as a switched input, and use the opposite voltage of what is input on the other side. If you use 12v on 85 as your switch input, you will need a corresponding ground on 86. If you use ground on 85 as a switched input, you will need 12v on the other side. Your switched input is really any signal that you would like to energize the relay but is not strong enough or is the wrong polarity to energize the circuit.

The top horizontal and bottom vertical pins (87 and 30) are the high current switch. when 85 and 86 have the right voltage, 87 will be connected to 30. If you supply heavy gauge 12v to 87, when the low current switch is energized that sme high current voltage will be on 30 through connection internal to the relay.

87a, the middle horizontal pin, is to supply a normally open signal to 30. When the relay is not energized, 87a is tied to 30. when the relay is energized 87 is tied to 30.

[SulphuriousSam]

Originally Posted by Joemomma1

What kind of vehicle has these? Wouldnt a 700R4 be simpler?

If you wanted an automatic. I believe he's talking manual tranny here. I may be totally mistaken but that's how I read it. And from my point of view if it don't have 3 peddles you might as well go get a lincoln continental haha.

[SulphuriousSam]

Actually the more I read this thread the more confused I am. I think that's my clue to pay some one else to mess with any transmission issues I have...

[gochoa]

Where's the fun in that!!! what the worse that can happen, take it to a mechanic????

I thought I was getting the wiring things, until I kept reading...damn, back to head scratching..

[kieth]

Originally Posted by joedoh

could you use a pair of relays and tap into the brake wire as a latching input, so that when you tap the brake the overdrive disengages? if the brake wire isnt the desired input you could put a brake switch on the clutch pedal and do the same thing. I can help you design that circuit if needed.







a relay is a low current to high current switch, it doesnt need a "ground" and no pin is required to have 12v "hot all the time"

looking at the bottom of a relay there are 3 vertical pins and two horizontal pins. the two outside vertical pins (85 and 86) are the low current switch, you can feed ground or voltage to either pin as a switched input, and use the opposite voltage of what is input on the other side. If you use 12v on 85 as your switch input, you will need a corresponding ground on 86. If you use ground on 85 as a switched input, you will need 12v on the other side. Your switched input is really any signal that you would like to energize the relay but is not strong enough or is the wrong polarity to energize the circuit.

The top horizontal and bottom vertical pins (87 and 30) are the high current switch. when 85 and 86 have the right voltage, 87 will be connected to 30. If you supply heavy gauge 12v to 87, when the low current switch is energized that sme high current voltage will be on 30 through connection internal to the relay.

87a, the middle horizontal pin, is to supply a normally open signal to 30. When the relay is not energized, 87a is tied to 30. when the relay is energized 87 is tied to 30.

If you would use the pole #'s and cross reference them to the colored wires then it might make more sense since no one else can see the #s on the realay itself.......Kieth

Here I went back and looked here is how they are numbered on the relay:

Blue--30 fused and direct to the battery

black 85 ground for relay trigger (low amp) I believe he is using this in conjunction with the govenor, when the govenor completes the ground it allows the OD to be engaged if the switch is turned on. When the speed falls below 30 mph the ground is no longer complete so the relay is turned off and the OD disengages? (is this correct)

White 86 trigger wire for relay (low amp draw) switch activates this circuit

Yellow 87 30 amp 12 volt switched (by white triggger wire) turns the OD on but it only supplies power when the govenor is above 30mph (it does this by controling the relay ground black # 85?

Red 87Q what I referred to as unused since it is powered only when the relay is not switched.......it could provide power to a accessory that needs power when the relay is not engaged lets say a burglar alarm ??

Kieth

[gochoa]

Thanks to everyone, finally making sense and doesn't seem like a "major" deal. Just need to sit down and follow all the input.

[Gianyveedub]

I did use a prewired pigtail. If you look at the relay in the photos, you will notice that the colors near the relay are different than the one I crimped them to. I use the diagram as my reference so I didn't screw up the wiring.

What really matters when you use a prewired pigtail is that the wiring on the pigtail is in the correct gauge (or maybe slightly smaller gauge...bigger wire) than what you are wiring. My ignition to relay wire (#85) is a pretty small wire because all it is doing is creating the charge for the electromagnet in the relay. The ones that you really need to look at are the Batt (#30) and the one to the Solenoid (#87). These two are carrying the 20 amps and need the big wire to handle the current. Hope this helps

[Gianyveedub]

Hello all. I finished wiring the relay to the truck and it works. For anyone who was looking at wiring these things and has seen how mine is done, I changed one thing. I changed how the indicator light lights up.

Instead of placing the ground wire for the light to the governor I grounded it to the truck. Reason for this is that I wanted the light to stay on when I have power from the ignition to the relay to let me know that the overdrive relay is on (also the overdrive after 28mph). Here is a diagram, I'll take photos this weekend to show what I mean.