My OD solenoid went out and to fix it I stole on off a spare transmission I got cheap a long time ago. I was looking for a replacement solenoid and these this are expensive, like $389 a piece. Add shipping and duties I´m facing 450 Euros or more until this like critter comes here. So I figured, why not try to fix what I have before I spend the big bucks. The problem with my bad solenoid is, that it does not stay in the engaged position. When I put Bat + to Terminal 4 it pulls fine, so the pull winding is probably fine. There is also a hold winding that is also fed by terminal 4, and that might be the culprit.
At least that is what I suspect to be at fault. I suppose the bigger wire is for the pull winding and the smaller wire for the hold winding. I ´m vey thankful for any kind of heads up or input. I´ll post progress on how I´ll screw this thing up even more, hahahaha
Isn't that thing usually red with arteries and valves?... Heck maybe someone here has a couple on their shelf collecting dust they can spare for helping a good fellow out for a reasonable value...it wouldn't be the first time. Hope you have successful surgery in the meantime...
This may or may not be home repairable... So the holding winding isn't working. There could be three causes; something is restricting the movement of the plunger. The coil is open. Or the holding contact is burned/bad. You'll have to undo the crimps to get it apart, once in you'll see the rest of the parts. Faults one and three will be pretty obvious and probably easily corrected. A open coil may be a different matter. If it's a obvious break where you can see it, fix it and move on. If you can't see a break, then it will need to be rewound. I'd recommend an electric motor shop that does rewinding to do this; you may find the two windings are interleaved, in which case you'll have to use a motor shop. In any case, it's worth exploring. Given what it will cost you for a new one, even with a rewind it may not be any more money....
In the early 1980s when mine went out the day before a 2,000 mile trip scheduled to start the next morning, I had to rig up something fast. With 4.88 gears, I could not do the long trip limited to 43-45 mph with a screaming Stude flathead six engine. I took off the o.d. solenoid, cut a hole in the end bell, exactly in the center to line up exactly with the plunger shaft. I welded a 1/2-20 nut to the end of the can and tapped the nut for a set screw to imitate a set screw collar I didnt have time to buy. It just so happened that the threads inside the "collar" nut helped grip the cable housing very well. This would act to hold a choke cable housing, so I could push and pull the O.D. solenoid by a choke cable on my dash. Inside the o.d. solenoid, I drilled the skinny shaft so I could thread the choke cable thru the shaft so I could push-pull the solenoid to operate the o.d. by using a choke cable on the dash. Manually shifting in and out of o.d. by using a choke cable worked flawlessly for the whole trip and for the whole next year as I designed my TH to Stude transmission adapters to put in a new-at-the-time 700r4 behind the Stude engine. This was 1980s If I ever use a Stude-Borg-Warner o.d. trans again, I would likely install another choke cable to operate the o.d. solenoid. I liked it that much WHY BE ORDINARY ?
Pretty easy to bench test. You have two wires, one to the solenoid coil(s), one for the grounding contact; on the bench without power applied, both should read to ground with the coil wire reading at an ohm value (sorry, can't find a spec but a SWAG should put it right around 1 ohm for a 12V unit). The other wire should be at or near zero ohms to ground. If you get higher values on either wire, you may have burned internal contacts. Note that there's two coils; a pull-in coil, and a holding coil. Both are switched internally by contacts when operated. To test, apply power to the coil wire. The plunger should pull in and stay pulled in. The sequence of operation is the pull-in coil pulls the plunger in and once it's reached full travel is disconnected by the internal normally-closed contact. The holding coil has no power applied until the plunger reaches almost full travel when a normally-open contact closes and powers the holding coil. So if the plunger pulls in but won't stay pulled in but cycles back and forth, you have a bad holding coil or burned/bad contacts. If it won't pull in at all, it's a bad pull-in coil or burned contacts again. The grounding contact should go 'open' when the plunger is fully pulled in.
I always look at E-Bay for used and/or obscure parts. Sometimes, at a pretty reasonable price, sometimes at a ridiculous price. I like the idea of a "manual", cable driven, solenoid replacement. Someone could even start a cottage industry in their garage/shop; you paying attention "dare-to-be-different" (you already have the experience)? I am Butch/56sedandelivery.
I have never had to deal with an overdrive solenoid, but I have repaired many other types of solenoids, and other point actuated devices. Before disassembling the solenoid, the first place I would look to troubleshoot the device would be the points ( contacts). Over time, the arcing caused by activating and deactivating the solenoid, will cause a buildup of material on the points, and there is also the likelihood that the points will have oxidized over time. The first thing I do is clean the points with a diamond file (point file), and in 99 percent of the cases, this solves the problem. If the points are inaccessable, but you can see them, electronics stores sell contact cleaning spray which will also help to clean them up. Bob
Try the contact cleaner spray before disassembly, and work the plunger in and out. It may be enough to get crud off the contacts and get it back to life. The contact cleaner usually has a long thin extension which can be used to stick into a little hole somewhere on the housing, and blast away. Don't be shy with this stuff, spray until it runs out, and it usually runs brown for a while with dissolved crud. Leave it to evaporate out, won't take long, and then bench test. Good luck!
You might be able to make a good one from two if lucky i have a spare one and i still run a od so wont part with it. Now you can try eBay and you might find one but probably not a guarantee it will be any better than yours. Clean well first just in case its cruddy inside.
I don't believe there is a set of "hold-in" contacts according to the diagram. Here's how to test both coils, assuming the diagram is correct. Put one lead of your ohmmeter at each of the points indicated below, one on terminal #4, the other to the body of the solenoid. You should see a very low resistance, like @Crazy Steve said, about one ohm. While watching your meter, manually press the solenoid plunger as far as it will go. When the plunger opens the "pull-in break" contacts you should see an increase (higher number) in resistance on your meter. If the meter goes to infinity it is an indication that your hold-in winding is open somewhere. Hopefully it's a bad connection, and not a break in the winding.
Thank you! You guys are great! That's a lot of good info. I'm out of town till Thursday but will update on what I find when I'm back home.
Never worked on one of these, but have worked on a lot of solenoid controlled devices. If you have a break in the hold winding, it is likely to be at the end where it leaves the coil and gets attached to the contacts. Roached contact points are more likely, though. Post some pictures of this when you get it opened up. I’m curious to see what you find in there. Sent from my iPad using The H.A.M.B. mobile app
Ok, I'm back at it, folks! This morning I opened the housing by bending back the little tabs that hold the coil in . The coils are wrapped in grease paper, but you can somewhat peek through. There is one black spot. I didn't have time to measure if one Or the coils ground out, but I will check. that tomorrow . There is nothing wrong visually in my opinion... So what do you think?
Thanks dare to be different! This was really helpful. I have a 4spd sag o.d. that I have been reluctant to put back in the car because of the bad solenoid and I like the idea of a manual control opposed to being at the mercy of trying to find 50yr old useable ones. (Saginaw solenoids can be hard to find and pricey) Sent from my SM-G550T using The H.A.M.B. mobile app
Might be a burn mark. Might not. You’ll have to peel the paper off. There’s a place not too far from here that can wind a new coil, maybe have to re-use the bobbin from your old one. Sent from my iPad using The H.A.M.B. mobile app
If you can't meter test it, have a smell! Cooked windings will smell burnt. and the enamel on the windings will go black if they are cooked. From what I see, they don't look cooked, but that can happen a few layers down, so you may not see anything on the surface windings.
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