The Stovebolt Site Forums The Shop Area Engine Shop 3 speed w/ overdrive trans hook up and ??

i am going to look at a 3 speed w/overdrive in the morning. these are totally new to me. it has to solinoid attached. does it work like the high/low rear switch with just two wires going to the unit? can i just use a switch like that if i install it? anything else i can look for to tell if it's good? it is a pig in a poke, the person selling it has never ran it? i thought these were kind of sought after but this guy is selling it pretty cheap. i always thought it might be a alt to a t5. thanks, hr

The Borg-Warner overdrive units are a very good solution to better highway gears. A bolt in replacement for the 3 speed transmission, with added cable control and a wire to the solenoid that can be controlled by a switch. I have done several of these conversions, and I'm getting ready to put one in my 1954 GMC. I highly recommend using one of these in a Stovebolt. The way to see if the unit is O.K. is to pull the shift cover and look at the gears, then move the shift lever of the o.d. to check for operation. Good luck!

thanks for the info. does the cable engage it or just the solenoid? seems like i remember seeing a picture of one of these on a car and it had a cable under dash. do i need a mechanical cable or just the wiring and switch? thanks

i was just wanting to know if i was going to be able to make it work with just the trans or i would have to hunt for parts specific to these just to make it work?

The cable controls the freewheel over running clutch inside the trans. Whith it locked, the trans works like a regular 3 speed. Unlocked, it allows the trans to shift into overdrive at roughly 28 mph, once you let off the gas for a bit to releive the torque load. This isn;t an exact speed, as it will vary depending on rear gear and tire size. You also have the option of free wheeling (no compression braking) when the overdrive isn't engaged but the over running clutch is unlocked (cable in).
The solenoid is what actually engages the overdrive gearset, it has 2 wires on it. 1 wire is the actuator wire (green on original harness) which is the pull in part, then a second which runs at a lower amperage that is the hold in, which keeps it locked in. There is also another wire in the system, and that is the governor. The governor wire connects to the ground side of the relay, and activates it when the cut in speed is reached. All of these wires lead back to a kickdown switch, which kills the power to the solenoid at roughly 3/4 throttle. Some people run a switch rather than the relay, and count on that to engage the od. I do have a switch on mine, but is connected to the relay, and is set up to operate as the factory intended. Only I can kill the power to it when od is not wanted, and the freewheel is usually locked out too.
The wireing harness is available, and a pto cable works best for the lockuot, however, the kickdown switch is not being repoped, and originals are very pricey. I have one on mine (I won't admit what I paid for it, but it was NOS), but so far, have never had to push it far enough to need to kickdown. The 235s torque is plenty to accellerate without it. As far as a relay goes, you'll want one that can handle at least 30 amps, preferrable with a built in fuse. I used a headlamp relay from Standard-Bluestreak, and hid it under a voltage regulator cover.
These trannies are definetly worth the effort, and drive very nicely while maintaining an original look.

Everything Bill said and like him I also like to run my solenoid wire through the govenor so one doesn't forget and leave the switch on and start off with the OD engaged. The govenor atomatically disengages the OD at a little under 30mph. I have a starter button on a home made bracket that the gas linkage activates when the foot feed is pressed ALL the way to the floor--this is my (cheap) kick down button. One wire is to ground and the other to the (Dist) side of the coil. This is not as good as a regular kick down switch but unless you stomp the gas pedal to the floor and hold it there, which would kill the engine, it works fine. Anything that momentarily kills the power will kick it into under drive and you can prove this by quickly turning the switch off and back on which will put it into under drive. This does not apply to a system that has something like a toggle switch that feeds current directly to the solenoid.

I have one of these behind a 235 in my 55.1 3100. I'm using the governor to control the solenoid. I'm so pleased with how well it works, I didn't even put in a switch to turn it off. I'm not using a kickdown at all. The benefits didn't seem to outweigh the additional complexity and fabrication effort. The rear end is a 3.90 and there is sufficient torque at 2000 RPM to provide adequate acceleration for passing on multi-lane highways. I don't drive much on 2-lane roads where I have to pass quickly, so I can't say whether or not it would work well there. The few times I've needed to, I just downshifted to 2nd with the OD still engaged. That seems to be a slightly lower ratio than 3rd without OD.

regards,

Leon

You can ground the base on the solenoid and apply 12V to the #4 terminal, if it clicks in and stays in the solenoid is good. To test the govenor: Put the body in a vise and insert the drive end into an electric drill. Using an ohm meter attach one lead to the terminal and the other to ground. Spin it up with the drill, if it pegs it is OK. The wiring is not difficult, just follow the diagram in the shop manual. As Bill noted a headlight relay works fine. I use a GM cruise control switch for the kick down. Lots of each available at FLAPS and wrecking yards.
Fred

i want to thank you all so much! i at least have a basic understanding of how these work now. i went ahead and bought it. in fact he threw in another 3 speed, a 4 speed shifter, a 3 speed shifter, and some other trans parts with the 3 speed w/ overdrive unit- all for $50! so i feel like i got a good deal. i should have enough stuff to make my project work. this is going to go behind a 292. i am considering putting it in my 53 hornet, but might put it in my 63 c10 since i don't really need the compound gear in the sm420 that's in it now. i would really like the overdrive for my 64 wrecker but i meed the low 1st gear in it. thanks again, hr