3 speed manual, w/ electric overdrive???

[my86442]

Ok im sure that ther is someone out there that can explain this one. How does the O/D work ( assuming 12v w/ ground switch) but what vehicles did these come with and how were the ratings on these?

http://waterloo.craigslist.org/pts/3471993224.html

Im a give this guy a call in the morning and see if i can go take a look at it and get some more info but info on here would be awesome too.

 

[pontiacgp]

I have never seen one so thanks to google...

3-speed manual overdrive units

How overdrive works
The governor powers the solenoid in the mid 20's MPH, you have to let up on the gas pedal to let it shift up. When you push the pedal to the floor the kickdown switch cuts off the power to the solenoid and temporarily cuts off power to the ignition coil so the engine stops running for a second or two. This lets the spring on the solenoid retract and shifts out of overdrive. When you drive less than the governor speed setting in overdrive it cuts off power to the solenoid.
If you are going up a hill and the car does not coast the solenoid will not retract and you will still be locked in overdrive. When you are in overdrive you can not go backwards. This was called the "hill hold" feature.
The pull out T-handle is used to lock up the trans into regular 3-speed mode. This is useful when pulling a trailer uphill and important when going down hill. If the handle is pushed in you can coast and not have any engine braking. When you were cruising and in overdrive second gear and some one pulled along side and wanted to race you could stick your toe under the gas pedal and push down on the kick down switch to gear down before hitting the gas and opening all three carbs.
When you wire in a toggle switch to operate the relay to power the solenoid you could shift it into overdrive in any gear and not have to be above the governor speed in first gear. Just like driving a big truck with a two speed rear end. Just remember you have to let up on the gas to let it shift up into overdrive and when you turn off the switch you also have to let up on the gas to let the spring retract the solenoid to shift out of overdrive. If you leave the switch on and are in overdrive you can not shift into reverse and you cannot roll backwards.

 

[Bonnewagon]

How old is that? Never seen one, but I like the concept.

 

[DRIVEN]

50s and early 60s. I don't think they are rated for much power or abuse. I have seen that overdrive adapted to the back of a Saginaw 4spd once. Not sure how much of a direct bolt on it was.

 

[pontiacgp]

I never knew this existed so this is interesting, the 3 speed and 4 speed use the same housing so it's a plug and play addition...

http://www.chevytrucks.org/tech/overdrive.htm

 

[DRIVEN]

It looks like the '65-up OD 3spd Saginaw can be bolted to the back of a 4spd Saginaw. The one in the ad in the 1st post is a "4 bolt" non-synchroed GM 3 speed. Not a Saginaw. Likely mid-late 50s vintage. I'd pass on that one. I still don't think they are as stout as a Saginaw. Most were behind 6cyls and some behind low performance V8s.

 

[my86442]

this is all new to me as well. I called the guy earlier today but no awnser. ill call back in a few hours and see if i cant go see it and get some info about it. 350 i think is his asking price but I will see what all comes with it andhow bad he really needs to get rid of it. Ill keep posted on this one. Obviously theres some intrigue in this subject

 

[autowizard]

I asked my dad about those old overdrives he said they worked great if you knew how to use them, the problem was you would forget you had it in overdrive and stall the car so the public never realy liked them. He was a gear head racer back in the 60s he liked them for cruising and trips and they held up well behind high horse engines and abuse. He also said back in the 60s you could buy a kit that would eliminate the electric part and run a cable. If i could find 1 i would use it in my car.

 

[my86442]

I asked my dad about those old overdrives he said they worked great if you knew how to use them, the problem was you would forget you had it in overdrive and stall the car so the public never realy liked them. He was a gear head racer back in the 60s he liked them for cruising and trips and they held up well behind high horse engines and abuse. He also said back in the 60s you could buy a kit that would eliminate the electric part and run a cable. If i could find 1 i would use it in my car.

How did the cable part work? theres one up the street from me and as soon as i get ahold of the guy to take a look at it, i think ill buy it, as soon as i get my taxes back

 

[autowizard]

Im not sure how it worked he didnt have any pics and he cant remember the details just something he remembered buying for one. If you can find an old timer that builds trans for a living you may get a lil more info on it.