R10 Overdrive Issue

[40cpe]

I see you said you have the OD relay feeding from the coil terminal. You need to be certain you have adequate size wire from the ignition switch to the coil and there is not a resistor ahead of your feed to the coil and relay.

If you want to by-pass all the circuitry feeding the relay you can install a temporary heavy wire from the battery post to the relay. Temporarily by-passing the ignition shouldn't cause any problems because the relay only energizes when speed is reached to the road or the relay grounded.

[fredv]

Thanks for the explanation regarding pilot lamp, I was thinking about something more complicate.

Originally Posted by 40cpe

I see you said you have the OD relay feeding from the coil terminal. You need to be certain you have adequate size wire from the ignition switch to the coil and there is not a resistor ahead of your feed to the coil and relay.

Yes, relay is feeded from the battery terminal of the coil, as indicated in the wiring diagram.
I don't think there is a resistor ahead, but size of the wire between the ignition switch and coil might be an issue...
I use gauge 14 from coil to relay and I think wire from ignition switch to coil terminal should be gauge 18.

Originally Posted by 40cpe

If you want to by-pass all the circuitry feeding the relay you can install a temporary heavy wire from the battery post to the relay. Temporarily by-passing the ignition shouldn't cause any problems because the relay only energizes when speed is reached to the road or the relay grounded.

Ok, I agree that relay shall energized the system when governor contacts closed at 28 mph.
When I tested the relay with ignition switch on, I had juice on feed terminal (from coil), and on TH SW terminal too (is that normal?)

When I ground TH SW terminal on the relay, both relay and solenoid are clicking.
It's indicate that relay and solenoid are working?

[fredv]

I took the car on the road this morning, with the test lamp connected to the solenoid terminal of the relay.
With the dash OD control handle pushed in (automatic position), the light burns at 28 mph approx. and I can hear the click of the solenoid when I listen carefully.
Just after the lamp burns, the grinding noise starts.
When I slowed down the car, the light stops burn at 22 mph meaning that governor and relay are working) with a little noise.
I stopped the car, I pulled the OD control handle out (locking mechanicaly the OD), and the lamp starts burn again at 28 mph and stop burn at 22 mph.
There was no grinding noise, but still little noise at 22.
It should mean that the electric system still works when the OD control handle is pulled out, as there is no rail switch on my transmission to shut down the electrical system.
Is it normal that the solenoid is always energized above 28 mph even if the OD is manually disconnected?
Then, I disconnect the ignition terminal from coil on the relay and after that, no noise at all from the transmission.
Did I miss something in the wiring diagram, and how the rail switch is replaced to cut the juice from the system above 28 mph ???

[Cecil/WV]

When I was having intermittent trouble with my OD, i mounted a truck clearance light under the dash with an alligator clip that could be moved under the hood. I clipped it to the terminal going to the solenoid and when the OD wouldn't engage, I could tell if the power was going through the rely or no. No light, relay problem, Light on, solenoid problem.

[40cpe]

Fred, the governor switch terminal will have a voltage reading on it if not grounded by the governor because it is the opposite end of the coil that is energized at the wire from the coil. Once grounded, it creates the magnetic field that pulls the points closed to energize the solenoid.

You are correct that the electrical system of the OD works when the handle is pulled out. It is normal. I don't think you can install a rail switch if there is no provision for it on the housing, unless you find a housing with provisions for it. You can install a manual switch to interrupt the governor circuit if it bothers you.

[Mike51Merc]

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Later OD systems omitted the rail switch entirely. I guess they decided it just was unnecessary.

It sounds like your electrical system is fully functional, but (besides the grinding) you haven't told us if it is upshifting and downshifting.

I think you have a mechanical problem.

[rotorwrench]

The shift rail blocks the function of the overdrive operating pawl when you pull the cable control out. It is also blocked while in reverse since the lever inside the transmission also controls the shift rail. The rail switch was only there to open the circuit so there would be no electrical energy wasted during manual transmission operation. I think the rail switch may have also started having reliability troubles so they just deleted it on further production after 1951.

You may have a problem with the ring & gear plate assembly or its interface with the sun gear where for some reason it's not locking the sun gear up like it should when the pawl engages it.

[fredv]

Seing the wiring diagram without switch rail, it seems obvious that the solenoid is always energized above 28mph whenever the dash control handle is pushed or pulled, but I was thinking that I missed something.
Thanks for the clarification.
The transmission is working without grinding when the dash control handle is pulled AND the OD electrical system not energized (with the power source from coil disconnected on the relay).
There is a grinding with system energized at the speed the OD is supposed to engage, and little noise when the car speed falls below 22mph (with the dash control pulled or pushed), no noise at all when electrical system is disconnected.
The rail seems to be operative, as it disconnect manually the OD.
Regarding electric controls of the OD, the only thing that I found is that when the solenoid is attached to the adapter for grounding contacts check with the white wire from the governor grounded, engine shall stop when the kickdown switch is pressed but it didn't.
I checked with the used solenoid and the new, and engine didn't stop.

The pawl engage the blocker ring during the test.
Ring and gear plate assembly were changed during transmission overhaul.

[Mike51Merc]

Originally Posted by fredv

Seing the wiring diagram without switch rail, it seems obvious that the solenoid is always energized above 28mph whenever the dash control handle is pushed or pulled, but I was thinking that I missed something.
Thanks for the clarification.
The transmission is working without grinding when the dash control handle is pulled AND the OD electrical system not energized (with the power source from coil disconnected on the relay).
There is a grinding with system energized at the speed the OD is supposed to engage, and little noise when the car speed falls below 22mph (with the dash control pulled or pushed), no noise at all when electrical system is disconnected.
The rail seems to be operative, as it disconnect manually the OD.
Regarding electric controls of the OD, the only thing that I found is that when the solenoid is attached to the adapter for grounding contacts check with the white wire from the governor grounded, engine shall stop when the kickdown switch is pressed but it didn't.
I checked with the used solenoid and the new, and engine didn't stop.

The pawl engage the blocker ring during the test.
Ring and gear plate assembly were changed during transmission overhaul.

The kickdown "engine killer" only works when the solenoid is engaged. That's what the orange wire is for.

[rotorwrench]

The ignition coil is only grounded for a split second. The time it takes for the solenoid to disengage which happens very quickly. If it is not getting it's momentary ground, then there is an open circuit somewhere. There may not be a good ground path or the solenoid is not going to full extension far enough to close the point set. There may br something blocking the pawl from shifting all the way in.

If you try a manual engagement of the overdrive by pushing the pawl in by hand, that would be the last mechanical test you could do to check function. If it still won't go into overdrive, it will be time to either pull the overdrive tail housing or pull the transmission and open it up on the bench.

[fredv]

Originally Posted by rotorwrench

the solenoid is not going to full extension far enough to close the point set. There may be something blocking the pawl from shifting all the way in.

I was thinking about something like that too. I will repeat the pawl engagement check again and measure exactly the lenght of the plunger.

Originally Posted by rotorwrench

If you try a manual engagement of the overdrive by pushing the pawl in by hand, that would be the last mechanical test you could do to check function. If it still won't go into overdrive, it will be time to either pull the overdrive tail housing or pull the transmission and open it up on the bench.

I will try to engage the OD by hand with a tool made from an old solenoid stem. I can't just pull the OD tail housing, I need to remove the whole transmission from the car....

[Bruce Compton, Canada]

I had a similar problem with my '54 Merc .The previous owner had connected the wire to the coil to the wrong side of the coil. Bruce

[Cecil/WV]

The OD pawl has a taper on the end that engages and I am wondering if it is in backwards,ie, needs to be flipped over?? Although, I'm not sure you could pull the cable out if it was Just thinking out loud. I do think that, unless its the wrong solenoid, that the problem is internal.

[fredv]

Solenoid is correct and electrical system is working.
It seems that the pawl engages the blocker ring when I'm turning the driveshaft by hand, but not when the engine is running.
I added a switch between the governor and the kickdown switch to cut the juice when the OD is manually disconected.

Here is what I found in the Borg Warner instruction manual:

Improper position of blocker ring:

1 - Occasionally, either in assembly at the factory or in service operation, the internal parts of the OD unit may have been rotated with the solenoid removed and the pawl withdrawn from its normal location. This may cause the blocker ring to rotate, so that its two lugs are not located with respect to the pawl. The solid portion of the blocker ring may be in alignement with the pawl, which will prevent full engagement of the pawl with the sun gear control plate.

2 - To test for this condition, remove solenoid cover, pull dash control knob out, roll the car 2 feet forward. Push dash control in, turn ignition switch on. Then, ground TH SW teminal of relay, and watch movement of center stem of solenoid. It should not move more than 1/8 in. when solenoid clicks.
Then, with the relay terminal still grounded, shift into low gear, and roll car forward by hand. Solenoid stem should then move an additional 3/8 in. as the pawl engages fully. These two tests indicate proper blocker action. Unless both tests are met, the blocker ring is probably not in the correct position.

3 - Rather than dissamble the entire OD unit, this condition may be corrected externally. With the transmission in neutral, and the dash control pulled out, move car forward one full turn of the propeller shaft. Then, loosen the two solenoid capscrews as far as possible, without removing and pull solenoid out as far as it will go, and hold it there while the propeller shaft is turned forward about 1/8 turn. Then push solenoid in and tighten capscrews.

I did the test 2 and it seems that the solenoid stem moves much more than 1/8 in. when energized, opening the 2 solenoid contacts.
Then, I shifted into 2nd gear and turn the propeller shaft by hand, and the solenoid stem moves again engaging the pawl as the propeller shaft was blocked in both directions.

The fact that the solenoid stem moves more than 1/8 when energized might be my problem.
Any ideas about that?

[40cpe]

The instructions read "should not move more than 1/8 in". Instruction #3 seems fairly simple. Why not try it?

[fredv]

I did it this afternoon with no result, the pawl and the solenoid stem doesn't move when I pulled out the solenoid.
I took the car for a drive, and no change.

[Gary Duff]

fredv

I have been following your problem here. From one of the photo's
I can see that the snap rings are missing that locate the shifting
sleeve on the sun gear. This would allow the sleeve to slide with
the shift fork and not bring the sun gear with it. Overdrive needs to
come apart. The grinding noise is the sun gear not traveling far
enough to engage.
Gary

[40cpe]

Originally Posted by Gary Duff

fredv


I can see that the snap rings are missing that locate the shifting
sleeve on the sun gear. This would allow the sleeve to slide with
the shift fork and not bring the sun gear with it.
Gary

I'm anxious to see how this plays out, and I know Fred is too. Fred has said that the transmission locks up/freewheels normally. That indicates that the sun gear is traveling on the shaft. Kinda looks like there is a lock ring on the side of the shift collar but it is hard to tell from the photo.

Fred will sort it out eventually. Most would have already given up.

[fredv]

Thanks for your support 40cpe. I will have to sort it out, these transmissions are almost unknown here in France.
Gary, the sun gear was not disassembled when I overhauled the transmission, so I would rather go for a problem related to the blocker ring...

[fredv]

I did all checks again and OD still doesn't engage.
I will drive the car without OD this week and remove the transmission from the car and overhaul the OD section again next week, unless someone find the solution. I do think the problem is related to the blocker ring...