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grassfiddler

Need Help with Gyro-Matic Transmission

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    Ok, I have been looking  and looking for what to do with the transmission on my 1952 Dodge Coronet. My car has a M6 gyro-matic transmission with fluid drive that I am trying to get working. When I bought the car all of the electronis had been disconnected on the trany. I rewired it all with new wiring according to the wiring diagram from my manual but now there is an issue in the car starting. The car would turn over but it wouldn't fire. So I unhooked the tranny wires from the resisitor/breaker to the coil and then the car fired right up. So I think there is an issue with the trany interrupter switch and or the solenoid. The manual says that it would be the resisitor that has gone bad but when I check it with my ohm meter it checks out at 12 ohms which what it is supposed to be.

    So with everything unhooked I fired the car up, then with a clothes pin hooked the wires back to coil. The car didn't die but when I go to throttle the engine it would want to die. Let off the gas and the engine smoothed out. Took it for a quick test drive and it stalled out like I turned the ignition switch off.

    Also, I have driven the car without the tranny electronics and in low range I can make it shift from 1st to second by using the clutch. I hear the click from the tranny, let off the clutch and It shifts smoothly, but when I put it in high range it goes to 3rd no problem but will not go into 4th. The top speed in 3rd is around 41 mph. I need to solve this issue as well.

    Any help would be greatly appreciated in figuring out how to get this working and also in where to find parts! I am new to this and need all the help I can get. It's either get this tranny working, hopefully at a reasonable cost or scrap it for a straight three speed that has less to go wrong with it. I can buy a 3 speed and all the linkage for less than what I'm seeing the electronic parts priced for on ebay. But I would like to keep the original tranny in the car.

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It sounds like you are having a problem with either the governor or the solenoid. The ignition interrupter is letting you know something isn't working right. Also, make sure your idle speed isn't too high. The governor regulates when to shift so having it too high will cause problems because the transmission will not recognize when to shift or downshift. My guess is the problem is in the solenoid. From experience, sometimes it just needs worked and driven to get things moving and working again. Make sure all of your wiring connections are good and clean too. Maybe take the solenoid off and clean it up. 

 

Look here for some guides for trouble shooting ideas:

 

http://www.imperialclub.com/Repair/Transmission/index.htm

 

Sorry I can't give a direct answer.

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Edited by 52b3b218

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The Imperial web site has a M6 Technician's training pamphlet (actually 2) on their website in the repair section.  They might prove helpful in getting yours diagnosed and put back in order.   Remember you are dealing with a dual range transmission with 2 gear ratios in each range.  The transmission was meant to operate in the upper range (what you are calling 3rd) for normal daily driving.  Low range was for driving in sand snow or towing etc.  So when operating correctly you need the clutch to move the selector between ranges and using reverse, but in normal use, you would usually select the high ranges 2 gears. 

 

Low gear in low range is really only needed if you decide to pull your house off its foundation.....

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Pull off the interupter switch to check it out. Make sure the interupter switch is open across both terminals-no continuity when the ball on the bottom of it is not pushed in. When you do push it in there will be continuity across both terminals. Also did you check the governer internally? Take the top cover 4 screws off and look at the points and spring for proper installation and that the points open and close properly. Points are normally closed and at idle/ and or low range speeds. The points are coated with silver, just carefully clean with a electric contact cleaner-no file or sand paper! Was your wiring install proper color coded  as in the schematic?

Sounds like the ignition points are being grounded out through the interupter switch to ground as governer speed increases and the points open.You need to be sure your wiring is connected exactly as in the diagram. 

 

Bob

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Pull off the interupter switch to check it out. Make sure the interupter switch is open across both terminals-no continuity when the ball on the bottom of it is not pushed in. When you do push it in there will be continuity across both terminals. Also did you check the governer internally? Take the top cover 4 screws off and look at the points and spring for proper installation and that the points open and close properly. Points are normally closed and at idle/ and or low range speeds. The points are coated with silver, just carefully clean with a electric contact cleaner-no file or sand paper! Was your wiring install proper color coded  as in the schematic?

Sounds like the ignition points are being grounded out through the interupter switch to ground as governer speed increases and the points open.You need to be sure your wiring is connected exactly as in the diagram. 

 

Bob

As far as I can tell I rewired everything like the diagram. I'll double check it again to be sure. Thanks everyone for the tips on what to do. Hopefully it will be a simple fix.

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That resistor could be your problem-I have never seen one fail but I read that they can. Good luck with it!

Edited by Dodgeb4ya

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The Imperial web site has a M6 Technician's training pamphlet (actually 2) on their website in the repair section.  They might prove helpful in getting yours diagnosed and put back in order.   Remember you are dealing with a dual range transmission with 2 gear ratios in each range.  The transmission was meant to operate in the upper range (what you are calling 3rd) for normal daily driving.  Low range was for driving in sand snow or towing etc.  So when operating correctly you need the clutch to move the selector between ranges and using reverse, but in normal use, you would usually select the high ranges 2 gears. 

 

Low gear in low range is really only needed if you decide to pull your house off its foundation.....

 

this might help you out like Greg G mentioned.... http://www.imperialclub.com/Repair/Lit/Master/012B/cover.htm

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That resistor could be your problem-I have never seen one fail but I read that they can. Good luck with it!

 

 

That resistor could be your problem-I have never seen one fail but I read that they can. Good luck with it!

I had no idea that these videos were on youtube. Talk about a wealth of info!!!! Love these old service videos. Thanks for posting.

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    Ok, just a quick update on the progress of the car. I worked on the car yesterday and looked at the things the others told me to look at. The interrupter switch turned out to be ok, as did the solenoid, and the governor. Rechecked the new wiring, all of the connections, and the circut breaker/resistor combo. All seemed right. So I was still stumped as to why the car wouldn't fire with the transmission wires hooked up to the coil.

    I then realized that I hadn't checked the anti-stall solenoid on the carburetor to make sure it was working. So I turned on the ignition and didn't hear a "click" from it or was it magnatizing either. I next ran a jumper wire from the battery to the anti-stall and low and behold it clicked and was magnatizing like it was suppose to. So my car has a ballast resistor in the negative power feed from the ignition switch to the coil that feeds the coil and the transmission circut. I checked the resistance at the resistor and I have 6 volts going in but only 2 volts coming out. Now the car would fire without the trans hooked up to the coil on the 2 volts, but when the trans circut was added it wouldn't do anything. So I bypassed the resistor with a jumper wire to get a full 6 volts to the engine and trany. With the resistor being bypassed I turned the key and the car fired right up. I took it out for a test drive and everything shifted and worked like it is supposed to! The only thing is, the top speed on the car is only 42mph.

    So I have two questions. 1} Do I even need the ballast resistor? I didn't want to put 6 volts in the system if it only needs, lets say, 4 volts and burn something up. The electronics for the trany are pretty pricey. But in the wiring diagram in my shop manuel it doesn't show a ballast resistor. And 2} Why is the top speed only 42mph? I know that the speedometer may be off and I could be going faster than what's showing or even slower but I want to make sure that I have everything right before I put this car on the road. What can I do or check to help get a little more top speed?

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I'm glad you figured it out! As for the speed you should be able to go far over 42 mph. I'm thinking your speedometer is not working right. Have someone follow you with another car and see how fast you are going. Also, what do you mean by top speed? like throttle to the floor? Or does is just sound like you are over revving the engine? 

Edited by 52b3b218

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I'm glad you figured it out! As for the speed you should be able to go far over 42 mph. I'm thinking your speedometer is not working right. Have someone follow you with another car and see how fast you are going. Also, what do you mean by top speed? like throttle to the floor? Or does is just sound like you are over revving the engine? 

When I get the car up to the 42mph it sounds like I have run out of gear, similar to what it sounds like when you are in 1st gear and the engine is reving like helk. So I guess I'm over reving the engine. Without a tach I'm not sure what the rpm's are when I'm running at the 42mph. As far as I can tell I'm in 2nd gear in the high range. Do you think that I could be having an issue with the breaker points not making contact at the higher speeds/rpms? Or maybe an issue with the fluid drive? I bought the car as a way to "slow" down, although my intentions aren't to drive at 70 I would like for it to easily run 45. How fast should this car be able to run?

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My 50 dodge doesn't have a resister. If changed to 12 volts you need one to keep from burning up points. I've had mine up to 80 with more to go./ Are you sure your getting in high range.

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You should not need any resistance tot he coil with a 6V system.  It surely did not come from the factory with one.  As far as top speed is concerned, are you sure you are in high range of the transmission?  Kinda sounds like you are in low range.  I forget what the shift pattern is for the M6?  what happens when the selector in in the other position??

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Did you read all of this booklet info that goes with the video? http://www.imperialclub.com/Repair/Lit/Master/024/cover.htm

The resistor prevents ignition cutout during the direct speed rail and interupter switch upshift operation.

 

 

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Sounds like to me you are still in third gear, and its not shifting into 4th. 3rd will run up to about 50 to 55 wide open. When driving, after you think it shifted, at about 27 or 30 put the pedal to the floor and see if it kicks down.The shifter should be away and down for high range, third gear position on a standard 3 on the tree. You should be able to let off the gas and shift out of 3rd at around 25 mph, let off, hear the click, and go again in 4th. 1st and 2nd are too low to run 42 I would think. I thought they came with a standard 3.73 with the m6. You should be able to run at 70 mph ok. 

Edited by 52b3b218

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My welding instructor inherited a 52 Coronet from his aunt and he complained the engine revved too high on the freeway. It had a factory 4.11 rear end. I swapped a 3.7 into it and he was a happy instructor. My test grades went up too! The rear end Ratio is stamped in a flat pad on the bottom of the rear differential pumpkin case.

Sounds like mentioned above that your trans has not automatically upshifted into high range. Even with a 4.11 rear end the car will do easily 55.

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Did you read all of this booklet info that goes with the video? http://www.imperialclub.com/Repair/Lit/Master/024/cover.htm

The resistor prevents ignition cutout during the direct speed rail and interupter switch upshift operation.

Yeah the trany resistor up by the aircleaner checked out good. I think someone at one time added a resistor in the power lead to the coil. So my wiring is as such, from my horn relay I have the power lead, then a ceramic resistor, then the wire to the negative side of the coil. I have 6 volts coming from the relay to the resistor, then 2 volts coming out of the resistor to the coil. It's this resistor that has me baffled. Is it needed to protect the electronics on the tranny from getting to much voltage??? See with the trany wires hooked to the coil the car will not start, and without them being hooked up the car starts right up. When I bypass the resistor with everything hooked up the car starts. The 2 volts is enough to start the car without the trany hooked up but not enough with it hooked up. So with the resistor bypassed it's getting the full 6 volts. If it's ok to bypass it then I'll do that, but if it's needed to protect the trany then I want to keep it. any thought on this???

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Your system was designed to run on 6V  (5 to 7.2 is likely the normal operating range)  Resistor is only necessary for 12V systems. 2V coming out of the resistor is too low to provide for spark and trans operation. 

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Here is some info on that resistor located in the little box on the air cleaner mount bracket.Sorry they didn't end up in the order I submitted the pages. Cannot fix it. Pics are numbered though. Jeesh what a hassle!

Edited by Dodgeb4ya

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there is a wealth of imformation here! I am awaiting the anti-stall unit myself..i will report if i learn something this weekend..but with superbowl in the way and my dash freshly painted...its gonna be a long shot!

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52b318  The shifter away and down is high range. Up like 2nd gear is low range.

I meant high and typed low. Thanks for catching that! Sorry about the mistake in writing that. 

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   So I finally had a little time to perform a couple of tests to see what is going on with the car. From the previous posts you'll know that I was having trouble with the car only going 42 mph as a top speed and that the car wouldn't start with the tranny circuit hooked up to the coil. That lead to questions, such as, is the tranny in high range, is the speedometer acurate, Is the wiring hooked up right, so on and so forth.

   The first thing I did was a little rewiring. I wanted to rule any of that out as a potential problem. I had already run all new wires for the tranny and the carburetor, so next I ran new wires from the generator to the regulator and from the horn relay to the coil. In doing so I did away with the resistor that someone added to the power lead to the coil. So I am now getting the full 6 volts to the coil and to the tranny circuit. Next I pulled the distributor cap and rotor. I wanted to check the spring tension on the breaker points. I kept thinking that just maybe there wasn't enough tension and at the higher rpm's that they were not making good contact. So I pulled the points, cleaned up an old set I had with more spring tension, and put those in the distibutor. Gapped the points and put it all back together. Turns out it was the breaker points that was the cause of the car not going faster than the 42 mph.

   Now the car starts right up like it should. So my next step was a test drive. In this test drive I wanted to check the high range on the tranny to make sure it was up-shifting and down shifting like it is supposed to do, I wanted to check the speedomter against my hand held gps, and to see if the car would go faster than the 42mph I had been going. I started out in high range, got to around 15 mph, let off the gas pedal, and it up-shifted. All is good so far. As I was driving I was checking the speedometer against the gps. I am happy to say that the speed was checking out to be right. I kept speeding up and got to 42 mph and pushed it past to almost 55mph before I ran out of straight away and had to slow down. Yeah! So far so good. Next was to check the kick down. It down shifted like it is supposed to.

   So that's the update on the car. Slowly but surely I'm getting the bugs worked out of it. Hopefully it will not be to much longer and I'll have the car on the road as a daily driver. Thank you to all who posted in helping me get this problem taken care of.

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Glad you got it going and thanks for coming back with a detailed solution of what you did and found out.

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Good to hear things worked out.  Thanks for posting a follow up.  Your solution may well help others.  The Semi autos were fairly bullet proof and it seems all the problems that have been discussed  relation to them not operating as designed have led to problems out side the trans, rather than an internal problem.  Congrats on your patience and perseverance.  Enjoy your clunkomatic.

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