Need overdrive help

whb52ford

whb52ford

Senior Member
I've been playing with this overdrive for over 20 years. It works sometimes, but not all the time. I have had it to our local transmission place twice, and once to a guy in Columbus Ohio who I was told was an expert in them. I have put on 5 different relay switches (all bench tested good), 6 solenoids (two from fifth avenue), two governors-one brand new. I ran a ground wire from the battery to the one bolt of the solenoid. I put inside the car two push button switches-one to over-ride the governor, and one to over ride the relay.

What I noticed today:
Battery was charging till it got to around 30 mph. It then went to a slight discharge. Stayed at discharge no matter what speed. Car would not shift into overdrive. I tried to over ride both governor and relay and nothing. I did notice that if I hit the kickdown switch, the battery went into charge. Once car slowed under 30 mph, the battery went to charge. Car goes into freewheel, but not overdrive.

Guessing electronics are working since battery dis-charging. Think the solenoid is taking draw in power, and since transmission is not shifting, it stays in draw in mode, and never shifts to holding mode (which needs less power). Think electronics are working.

I would think that mechanically, it would work or not work. Confused why it works sometimes and not other times. Really frustrated with it.

I'm to the point I'd like to take it someplace and have somebody that knows these things, talk to me or fix it for me. I'm worn out playing with it.

Bill 814-868-0177 Erie, PA william_bachmann@hotmail.com
 
Sounds like something screwed up in your wiring. When you see the discharge the battery voltage drops below the point some relay or solenoid drops out or won't pull in. G.M.
 
Grounds! Run a cable from trany to frame, engine to frame too. All wiring in the overdrive circuit must be 30 amp rated or won't pull enough juice to activate the OD - if you're still 6 volts.
 
Still 6v. If overdrive kicks in battery reads ok. Only discharges when should be in od but not. I also have a ground from engine to body.
 
Had same problem for years it wouldwork an then it would not work it was the generator sounds kind of funny but tat was my problem good luck Rog
 
The solenoid has two set of contacts one allows the solenoid to pull, the other to hold the solenoid until power is released by the relay. Your description seems to say that the electrical portion of the system is working, but the engagement is having mechanical problems. Having replaced most of the electrical parts, governor, solenoid, etc, I suspect that the "balk ring" that is operated by the solenoid is jaming. It can also be from a problem with the adjustment of the dash control. When the handle is pulled out, it moves the shift rail. This rail is also actuated by a cam on the reverse fork inside the transmission. Otherwise the vehicle can't back up. If you need a circuit diagram, I can post it.
 
I don't know what the bulk ring is, but I'll bet that is the problem. Is that something that can work sometimes and then not again. Od works about 10-15 times, then done for the day. I don't drive it every day, but next time, it's the same thing. About the handle. I know I can back up with the handle in or handle out. I do know that when I push it in, it is going as far as it can. Tell me more about the balk ring. thx
 
Clean the generator. It would charge and then it would not. It takes lots of current to kick in over drive. It needed new brushes and a good cleaning. Took me a long time to figure this out. Generator would charge for days then it wouldn't. Just give this a try my sound stupid but it fixed my overdrive problems.
 
As noted above, the solenoid has two electromagnetic coils, the first one (high current)throws the solenoid and the second (low current) holds the solenoid. When the solenoid shaft fully extends, internal contacts disconnect the first and power the second.

If your ammeter shows a steady discharge, then it seems that the first is not fully throwing the solenoid and is continually drawing current.

I had a similar problem and found it was related to a low-voltage condition in the overdrive power source, because the wire was too thin. When the voltage was lower (like at night when the headlights were on) the OD solenoid would only partially extend, the OD wouldn't upshift, and the ammeter showed continual discharge.

To diagnose this, take a voltage reading at the battery and then at the OD relay. Try it with the headlights on and the engine idling.

The cure is either the connections are bad or the wire gauge is too small, or your battery is weak, voltage regulator maladjusted, or generator isn't putting out enough.
 
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I kind of thought the power supply was not good. Since power goes through the ignition switch, I replaced the ignition switch to make sure I was getting out what was going in. I bought the wiring harness for the car from ??? years ago. The wire is heavy enough. I keep going back to not full power coming through ignition cable. Was thinking about putting in a relay that would power directly to solenoid. Any ideas on that?
 
whb52ford said:
I kind of thought the power supply was not good. Since power goes through the ignition switch, I replaced the ignition switch to make sure I was getting out what was going in. I bought the wiring harness for the car from ??? years ago. The wire is heavy enough. I keep going back to not full power coming through ignition cable. Was thinking about putting in a relay that would power directly to solenoid. Any ideas on that?
Click to expand...

I'm not a big fan of adding relays to stuff unless they're really needed. You need a good diagnosis before you start surgery.
 
whb52ford said:
I kind of thought the power supply was not good. Since power goes through the ignition switch, I replaced the ignition switch to make sure I was getting out what was going in. I bought the wiring harness for the car from ??? years ago. The wire is heavy enough. I keep going back to not full power coming through ignition cable. Was thinking about putting in a relay that would power directly to solenoid. Any ideas on that?
Click to expand...

Need to check it, other wise your just guessing, use a volt meter. The voltage into the switch should be the same as the voltage out. If that checks ok, then check the voltage at the other end of the wire to see if there is any voltage drop there.
 
I know I'm not getting 6v out of ignition switch. I'm getting about 5.0 volts. Think I read I need 4.5 to power relay. I have a new wiring harness, think I got it from YnZ and it's like original, not cheep stuff. New ignition switch, where am I losing voltage?
 
There is a problem somewhere, you should not be seeing a voltage drop. Using your numbers, that would be at least a 17% drop across a switch which should not have any noticeable drop. Attempting to rely on 4.5 - 5.0v to reliably throw a 6v solenoid does not seem like a good idea. Not running the battery should be above 6v and running up around 7 something.
 
Problem is probably the switch itself. That's where I would start.
But, then again, I like relays
 
The switch I replaced it with was a brand new one out of the box. Could I have put in a bad switch? How can I test the switch to see if that is the problem?
 
If you will do as JT FORD did and install a #12 wire from the battery hot side of the starter solenoid to the input side of the relay, you will have some confidence that it is or is not voltage related. The solenoid will not engage until the governor kick it in, so there will be no power drain from it. You have spent mega bucks on the mechanical side, try this simple test.
 
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