Borg warner overdrive troubleshooting

Well I found the trouble this time, the tab that holds the pull in points apart when the solenoid is engaged slipped, allowing them to remain closed while the solenoid was engaged, shorting it out. I was able to get it apart and moving again and I cleaned the points up but it still smells really burnt, when I bench tested it, it does move but not strong like it should and not enough to even overcome the spring to open the pull in points. Note that it is stuck engaged in this picture. So much for my new reproduction solenoid...
 

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Automotive Stud said:
Well I found the trouble this time, the tab that holds the pull in points apart when the solenoid is engaged slipped, allowing them to remain closed while the solenoid was engaged, shorting it out. I was able to get it apart and moving again and I cleaned the points up but it still smells really burnt, when I bench tested it, it does move but not strong like it should and not enough to even overcome the spring to open the pull in points. Note that it is stuck engaged in this picture. So much for my new reproduction solenoid...
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I had exactly the same thing happen on a repop solenoid. Did you get it from 5th Avenue Antique Auto in Manhattan, KS?. You might contact them and explain the problem, maybe get a refund or replacement. If you get another one by whatever means it would pay to check it out internally before you install it. I learned the hard way...
 
The coil is likely fried. Time for another one. I've been lucky getting used ones off the flea-pay. They generally just need cleaning and little lube in just the right spots. They made things well back in the day.
 
Thanks for all of the help guys. One quick question, I see a seal listed that fits between the solenoid and the transmission, 240698 is the national number. Is this the seal that is pressed into the solenoid or is there one that goes into the transmission also?
 
The seal is pressed into the solenoid, there is no seal on the transmission side, the seals purpose is to keep oil from getting into the the solenoid electrics. The seal is a rubber gasket pressed inside of a steel casing. This unit is then pressed down around the shaft into a "seat" in the solenoid casing.

I replaced mine once and a word of warning is that removing the old seal can be difficult, with the risk of scratching the solenoid shaft or the seating. If scratched, then this can cause it to leak.

Good luck

p.s. - one tip on the whole setup is to by-pass the old relay and use a modern relay, with fuse. This allows for much easier testing of the system, and if you want to keep it for the long term, it is easier to maintain.
 
This overdrive is going to be the death of me. I bought another new solenoid, when bench tested it works great, when I put it in the car the solenoid always works but it doesn't always push in far enough. I even took the cover off of the solenoid with it installed to watch the movement, I jacked up the rear of the car, and with power going to the solenoid it engages, when I rotate the driveshaft it doesn't always engage the rest of the way. It almost seemed like it engaged all the way more when I had the solenoid bolts lose. What's going on now? I'd really like to have this nailed down by the weekend!
 
I wish I knew more about overdrive to help, just a thought, if the trans is moving at speed it takes the back pressure from the rear end to shift, may be what your needs. I would give it a try.
 
With mine I can go through the gears and it won't shift to overdrive till I let off the accelerator, its like the back pressure assists it shifting.
 
I thought that's how it worked, I was letting off of the gas to the point where the car was slowing down, also while it was freewheeling I tried keeping the rpm's around where they would be if it was in overdrive and neither seemed to help it engage.
 
I would recommend checking the pawl detent spring, the pawl, the housing, and the balk ring & plate assembly. It sounds like something inside is not right.
 
I've been trying to avoid disassembly since it does work intermittently but I might have to. One other thing I noticed, the manual says if the cam retaining springs are weak the unit will freewheel at all times. I noticed with everything electrical disconnected mine freewheels at all times if the Overdrive handle is in but the solenoid is engaged. Is that normal or are my springs weak?
 
If the spring leaves are too weak to hold the rollers in position, there is a chance that the the overdrive shaft would freewheel and not turn the rear axle when engine power is applied to the transmission after the governor turns the power off to the solenoid at low speed. A person would have to lock the overdrive out to get going again.

One thing you need to make certain of is that you have the correct wire gauges in the operations circuit and that all your grounds are good. If the solenoid doesn't receive the electromotive force it needs then it may not have enough power to function correctly. If you are absolutely certain that it does, there is something blocking proper function of the pawl and full engagement.
 
Greg58 said:
With mine I can go through the gears and it won't shift to overdrive till I let off the accelerator, its like the back pressure assists it shifting.
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It's not back pressure, it's the removal of driving torque that allows the upshift. Same thing happens when you kick it down and the ignition is interrupted for about 1/2 engine revolution. It removes the driving torque to allow the downshift to direct drive.
 
Dobie Gillis said:
It's not back pressure, it's the removal of driving torque that allows the upshift. Same thing happens when you kick it down and the ignition is interrupted for about 1/2 engine revolution. It removes the driving torque to allow the downshift to direct drive.
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IIRC, there's a switched wire in the factory OD circuitry that defeats(?) the power connection from the coil to the points. It causes the engine to very briefly hesitate for this purpose.
 
Correct. The kickdown switch interrupts the power to the relay and momentarily grounds out the ignition at the same time. Grounding out the ignition removes the driving torque from the OD so the solenoid plunger can withdraw, allowing the downshift to direct drive.
 
Thanks everyone for the knowledge, it seems to be working great now! I think a lot of it was a learning curve for me learning how to drive and what to expect with one of these transmissions.
 
Good to hear it is working, it does take a couple of times to understand when to let the O.D. shift in. Sorry everyone for the way I worded the posts earlier, I should have said something like the engine braking releases the torque so the overdrive can shift. I bought a kick down switch when I started getting everything together for mine but haven't found it needed, I may at some point install it, my car pulls good even in o.d.
 
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