I'm trying to fix the overdrive on my 53 Ford (6 cyl). I initially thought the solenoid was bad but pulled it and it bench tested fine. I was told the overdrive wasn't working when I bought the car so I didn't experience the problem first hand. I now know the overdrive functioned until you hit the kick down switch. When you do that the solenoid engages and disengages repeatedly making the car "buck". It sounds to me like there's a short somewhere in the circuit but I have zero experience with overdrive. Anyone out there have any experience with this? I have the Borg Warner Manuel but it doesn't address this issue per se. Just fully not engaging or not disengaging. I'm thinking of getting a new overdrive wiring harness since they're only around $30 but don't want to waste the time or money if it's a bad relay or kick down switch. Any help is appreciated.
The kickdown functions by shorting the ignition to ground (removing power/unloading the transmission) when the gas pedal is pressed (via the kickdown switch), then when the solenoid 'shifts', a set of contacts inside it clears the 'short'. Sounds like those contacts are bad or dirty. Pull the solenoid, disassemble, and check/clean the contacts.
The solenoid is functioning properly though. I pulled it and it extended when energized and retracted when not. It stayed extended as long as it had power, no moving in and out.
Are you still 6 volt? If so how are you bench testing - also just because it bench test ok doesn't mean once it's it the trany it will function correctly. Relay contacts are very important. Grounds are very important. If you're still 6 volts - wiring condition will be an issue AND if they've been replace are they ( ALL WIRING DEALING WITH THE OVERDRIVE ) 30 amp gauge rated - anything less will affect the OD option. If you're still 6 volts battery and generator output is critical for OD operation. All connections and contacts must be perfect - I can't express this enough. Do you have the blue bible - this is very helpful. Once you get the OD working its a real joy driving the car. Hope this helps - been there done that - LOL!
It's still 6 volt. Most original wiring. The overdrive was working with everything the way it sits now. I tested the solenoid by grounding the body to the positive side of battery and the negative wire to the negative post. I've got the shop manual, Motor manual, and the overdrive manual.
Great - the system is very sensitive to getting the amps to activate the solenoid. Mine always worked during the day, but at night with the lights on would give me fits. All new wiring, bushes cleaned in the solenoid and relay. All wires grounded good, etc. I concluded the generator needed rebuilt but sold the car before I did it. And remember the kick down switch and governor wiring. Now you can always convert to 12 volt - not too hard or involved. Good luck.
Besides the kickdown problem, is it otherwise running properly? Sounds like a wiring or kickdown switch problem. Those switches are placed in a location that accumulates a lot of dirt and moisture. My old switch was a mess inside and I replaced it with a new one for about $35. As far as the kickdown harness goes, it's just 4 wires that are easy enough to replace for next-to-nothing in cost. By the way, I've found that the kickdown feature isn't all that important because the gear ratio of second-overdrive is nearly the same as third-underdrive. In other words, I just manually downshift to second-over for passing gear like a regular manual transmission.
I almost bought a '53 that the owner bypassed the relay with a toggle switch. Very simple - I was going to try that with my '50 but sold it. I don't think it had a kick down either.
I just remember a guy on here or another Ford site having troubles - had all new wiring, relay, solenoid rebuilt - everything right as right - turned out that the solenoid rod was hanging up in the trany due to the way it can be installed wrong. Can't remember the exact cure to the problem. Do a search on here, The Ford Barn , and shoeboxford.com.
Re-pulled the solenoid and took it apart, cleaned and filed the contacts. Checked the wiring. It's working like a charm now. Thanks for the help, gentlemen!
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