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Fluid Drive Transmission Won't Upshift


spitfire

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Hey everyone,

I'm having some trouble with the fluid drive transmission in my '50 Chrysler Windsor. I'll give you the story and a little history on the issue. Brace yourselves, it's a long one.

I remember, shortly after purchase, the car had a couple episodes where it didn't want to up shift. I remember turning onto a back road to limp it home and, after letting off the throttle (I was trying to coax it into working), it made a single, hard up shift, and then it would be fine. After rebuilding the generator, replacing the battery, and cleaning the contacts in the voltage regulator, I found that these issues just about vanished, apart from the very occasional no downshift or hard up shift when driving around town. This is very rare and has only happened a few times in the couple years I've owned the car.

 

A few weeks ago, when merging onto the freeway, I had to kick it down to get out in front of somebody. After that, the car wouldn't up shift. I had to pull off to the side of the freeway. Of course, it decided to up shift right when got off onto the side of the interstate. I came to a complete stop and then merged back onto the freeway, once traffic cleared up. The car did a nice, quiet, but solid up shift and I continued on. A few miles later, I left the freeway and came to a stop at a light. When the light turned green, I took off and when my foot let off the accelerator for up shift, the car made an extremely hard up shift with a loud "bang", which shook the whole car. I then could no longer up shift. I was right around the corner from my house, so I got it home and ended up driving it around in the neighborhood to try and see if it would up shift. After lots of attempts, it would up shift, but very late. Maybe when I hit 25, it would finally up shift. I inspected the wiring for the transmission and found that it was in very bad condition, so I ordered a new harness from Rhode Island Wire and installed it.

I took it back out on the road and after one mediocre shift, everything was almost perfect. Smooth, quiet shifts, seemed just a little bit late though, still. The next day I used it to run some errands, but later in the day, while on the freeway, it decided to downshift while doing close to 60 mph. I'm lucky it didn't seem to do any damage to the 95K mile original flathead. I got off the freeway and limped it home, as it would no longer even attempt to up shift.

 

It seems to me that I checked the fluid level in the fluid coupling just a few thousand miles ago and it was right up to the filler hole. I haven't seen any new stains under the car. I haven't ever changed the fluid out, however I've been meaning to with ISO 32 hydraulic fluid. I believe that was the closest thing to the original ISO 22 that you could readily obtain from a local store.

 

Do any of you know what could cause this no up shift condition? Could it be a solenoid or governor issue? It seems to be intermittent, so I would think (hope) that it's nothing internal.

Thanks for reading this long post,

Dan

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    I have this type of transmission in my 52 Dodge. I'm no expert on these but there are a couple of things to check. The fluid in the tranny is seperate from the fluid drive coupling. That's the first place I would check. Pull the access cover which should be located on the passengers side floor board on the tranny hump. When you pull the cover you will see the solenoid, governor, and the interuptor switch, as well as the plugs for the oil. Fill or replace the oil. It takes SAE 10W or SAE20W if you can't find 10W. Also there is a member on here that has told me that modern SAE 5W-20 works well in his tranny. You'll need 3 pints according to my manuel.

     If that doens't clear up your issue, then next I would go to the chrysler imperial website and find the repair section on our type transmissions. It explains how to test each solenoid, governor and the interuptor switch. There is also some great repair vidoes from Chrysler on youtube. These were videos that were sent out to the repair shops back in the 40's. They walk you through step by step in what to check and are very easy to follow. Also, if you don't have a repair manuel I suggest buying one. Reprints can be found on ebay for around $30. They too will tell you how to trouble shoot the tranny and all it's parts.

    Some of the possibilities it could be are, low oil, governor points are failing to open, excessive engine idling speed, direct speed rail piston sticking in cylinder, loose shifter fork lock screw, damaged direct speed blocker ring.......

    You can check the solenoid by simply turning your key to the on position and placing a metal object such as a screw driver to the solenoid. If the solenoid is working it will become magnatized and will attract the screw driver. The contact points in the governor could be going bad. Remove the 4 screws and top plate. The points are attched to the top plate. Inspect, if they need cleaning use a silver cleaner. Do not use sand paper or a file. It will ruin them!

    What I learned with my tranny is that I had the engine idle speed up to high. There were a couple of things causing that on my car. The first was in my carb adjustment, the second was in my carb to gas pedal linkage, it was sticking a little, and the third was in the pedal itself. After cleaning and readjusting I was able to get the RPM's back to the 450 to 475 the book calls for. If the RPMs are to high it makes the electronics think that you are still accelerating and it won't upshift when needed. Also I found, when in high range, that if I let the car shift around 15 to 20 MPH's that I get a smoother shift. When above 20 it shifts much harder.

    I would also check the kick down at the carb just to be sure the connections are good as well as checking the resistor and breaker up by the air breather. These M6 transsmissions are pretty common in Chryslers, Desotos, Dodges, and some times Plymouths. They have a variety of names like "tip-toe shift" and "gyro-matic". They are all the same tranny. There are however a couple of minor differnences in wiring of the electronics and location of the interuptor switch. So just be aware of that when comparing and buying replacement parts from differnt year models. For the most part every part is the same across the board and will interchange from make, model, and year. So any repair manuel from any of the various "Chrysler" products will tell you the same repair and trouble shooting info as well.

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Is your RPM's above 450 475 at idle - if so no upshifty

By the way you use a Tach and Dwell to figure that out.

In this order:

Set points, around .020 

Check Tach and Dwell - Dwell at @38Degrees RPM's @ 450

Set Timing @ 2 AFTDC

Use a Vacumn Gauge to set at highest reading @ 20" steady

Check RPM again around 450 -475 at the highest

Reset Vacumn again at highest setting.

Same problem run diagnostics for transmission using a service manual

Check Transmission Selenoid Relay for blown fuse - wires tight and all units grounded with star washers. etc. etc. etc

One more thing a sticky linkage can screw up RPM's also - clean clean clean dem linkages

Good Luck

Edited by Tom Skinner
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