PhilJohnson Posted August 30, 2011 Report Share Posted August 30, 2011 I have a clunky and clacking M6 in my Coronet at the moment (car clunks and clacks as it comes to a dead stop). I have the option of picking up a 3 speed manual (unsure if it came from a Plymouth or Dodge). I've heard that some fluid drives had regular 3 speeds behind them. Do three speeds have different input shafts for fluid drives versus a standard clutch? I was thinking of just putting the 3 speed in place of the M6 transmission and re-using my current clutch/flywheel setup. Quote Link to comment Share on other sites More sharing options...
Young Ed Posted August 30, 2011 Report Share Posted August 30, 2011 I have a clunky and clacking M6 in my Coronet at the moment (car clunks and clacks as it comes to a dead stop). I have the option of picking up a 3 speed manual (unsure if it came from a Plymouth or Dodge). I've heard that some fluid drives had regular 3 speeds behind them. Do three speeds have different input shafts for fluid drives versus a standard clutch? I was thinking of just putting the 3 speed in place of the M6 transmission and re-using my current clutch/flywheel setup. Yes the fluid drive bellhousing is much deeper. Other than swapping a proper input shaft in its a pretty straight forward swap. The m6 and 3spd are within 1/2 inch of each other in length so no driveshaft mods. You will have to track down or modify some 3spd shift linkage. Quote Link to comment Share on other sites More sharing options...
55 Fargo Posted August 30, 2011 Report Share Posted August 30, 2011 I was looking at my M5 trans it is 15.5 inches long, from front edge to outside edge of brake band drum. My 3spd trans from a 1951 Plym, is 19 inches long from front trans case edge to rear edge of brake band drum. I know for my set-up, on my 47 Chrysler, it went from suing a fluid drive coupler to dry clutch, where the clutch hosuing is much shorter, resulting in having to move rear engine mounts forward 3-4 inches. The longer 3 spd trans compensated this change, resulting in using the same drive shaft with no modification. I am not sure thi is not unique to my canadian set-up or not. 1 idea is to get a trans from a 3sp fluid drive , and if it is longer, you may have to mod the driveshaft, but I am no expert in this area, and Ed probably knows what is needed.... Quote Link to comment Share on other sites More sharing options...
Young Ed Posted August 30, 2011 Report Share Posted August 30, 2011 Fred the swap I helped with was in a 51 dodge and the clunk-o-matic we took out was almost the same length as the 3spd with OD we put in its place. Perhaps the M5 & 6 are not the same length? Or am I confused that a gyromatic isnt an M6? Quote Link to comment Share on other sites More sharing options...
55 Fargo Posted August 30, 2011 Report Share Posted August 30, 2011 Fred the swap I helped with was in a 51 dodge and the clunk-o-matic we took out was almost the same length as the 3spd with OD we put in its place. Perhaps the M5 & 6 are not the same length? Or am I confused that a gyromatic isnt an M6? Not sure, this M5 is a shorty little guy, and the 3spd trans I have looks the same as most of the other units I have ever seen. Ed, how long is the R10 OD trans compared to a regular Dodge 3spd trans. I am hoping if I do get the one i am after, I will not need to doa drive shaft mod....Fred Quote Link to comment Share on other sites More sharing options...
Young Ed Posted August 30, 2011 Report Share Posted August 30, 2011 Not sure, this M5 is a shorty little guy, and the 3spd trans I have looks the same as most of the other units I have ever seen.Ed, how long is the R10 OD trans compared to a regular Dodge 3spd trans. I am hoping if I do get the one i am after, I will not need to doa drive shaft mod....Fred Not including the input shafts the OD and standards are identical length. The short wheelbase cars have a short no tailshaft 3spd but thats a whole diff animal. Quote Link to comment Share on other sites More sharing options...
greg g Posted August 30, 2011 Report Share Posted August 30, 2011 what would you do for shift linkage? Can the Semi stuff be converted to shift a stadard?? Quote Link to comment Share on other sites More sharing options...
Young Ed Posted August 30, 2011 Report Share Posted August 30, 2011 what would you do for shift linkage? Can the Semi stuff be converted to shift a stadard?? Greg the one we did the owner had different rods out of junkyard cars and Dad found 2 that worked after a couple bends. The interior stuff all stayed the same. Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted August 31, 2011 Report Share Posted August 31, 2011 M-5 (Late 1942-48) and M-6 (1949-53) Transmissions are totally different in lengths. M-5's are much shorter that the M-6's. Quote Link to comment Share on other sites More sharing options...
55 Fargo Posted August 31, 2011 Report Share Posted August 31, 2011 M-5 (Late 1942-48) and M-6 (1949-53) Transmissions are totally different in lengths. M-5's are much shorter that the M-6's. well that would make sense Rob. On my car it had a fluid drive and M5 trans, then it had the dry clutch and 3 spd standard trans installed, requiring the rear mounts to move forward, but the driveshaft did not require and modification. If I had had a M6 trans, it would have needed a different length driveshaft for my current set up.. Quote Link to comment Share on other sites More sharing options...
Rusty O'Toole Posted September 1, 2011 Report Share Posted September 1, 2011 Will the Fluid Drive gearshift linkage work with a 3 speed? Seems to me it would be one speed short? Quote Link to comment Share on other sites More sharing options...
greg g Posted September 1, 2011 Report Share Posted September 1, 2011 see post 8 Quote Link to comment Share on other sites More sharing options...
PatS.... Posted September 1, 2011 Report Share Posted September 1, 2011 (edited) Before you turf the M6, change the fluid including the fluid coupling with the correct fluid. James Douglas did some very in depth research to determine the closest modern equivalent to the Mopar fluid. That post is on this forum. http://www430.pair.com/p15d24/mopar_forum/showthread.php?t=14203 Remember that the fluid coupling (looks like a torque converter) and the M6 are separate units and take different fluids. Next, check that the ebrake is not grabbing, that will make proper shifting almost impossible. A dragging service brake will also raise he!! with proper shifting. Check for correct idle for the M6. (500 rpm at idle) Check for bad grounds, broken wires or dirty connections. Ensure you have the proper carb with dashpot and kickdown. Also, remove the governor, take off the top and clean it up inside with brake cleaner to loosen all the weights. The above are the basics to look for when shifting is erratic. The Imperial Club site has a detailed troubleshooting "booklet" on the M6 that may be worth a look as well. http://www.imperialclub.com/Repair/Lit/Master/024/cover.htm The M6 is virtually bulletproof inside but the peripherals need to be clean and tight. The swap to a standard is possible, but the above is much easier and cheaper, especially if it solves the shifting problem. Good luck. Edited September 1, 2011 by PatS.... Quote Link to comment Share on other sites More sharing options...
55 Fargo Posted September 1, 2011 Report Share Posted September 1, 2011 Will the Fluid Drive gearshift linkage work with a 3 speed? Seems to me it would be one speed short? This linkage works just fine, it is the trans gear selector itself that is different. I am using linkage for an M5 trans on my regular 3spd trans, for years now. The clutch release bearing rod, on a dry clutch is much shorter than witha fluid drive clutch.... Quote Link to comment Share on other sites More sharing options...
Young Ed Posted September 1, 2011 Report Share Posted September 1, 2011 Right its the transmission that controls the fact that there isn't 4 positions. You hook that same column up to a standard 3spd and the 4 positions are there. Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted September 1, 2011 Report Share Posted September 1, 2011 M-5 and 6 transmissions do have their mechanical internal problems. Input shaft and blocker ring and sleeve wear will cause awful banging in and out of high range. The repair requires a new input shaft and direct speed sleeve and ring to repair correctly. The later M-6 transmissions can make a noise from a severely worn gear rotor oil pump housing wear (Pump is built into the extension housing). Loss of oil pressure will then cause popping out of high range too. Have repaired lots of these transmissions. Input shafts are really hard to find new any more. Bob Quote Link to comment Share on other sites More sharing options...
PhilJohnson Posted September 19, 2011 Author Report Share Posted September 19, 2011 I can't believe I didn't catch this before. Guess I'll have to check my threads more often Good luck. Thanks. The transmission shifts fine, no problems there. It is at low speeds that it clunks (like under 10 mph). Doesn't seem to affect take off. I looked at the e-brake it's fine. M-5 and 6 transmissions do have their mechanical internal problems. Input shaft and blocker ring and sleeve wear will cause awful banging in and out of high range. The repair requires a new input shaft and direct speed sleeve and ring to repair correctly.The later M-6 transmissions can make a noise from a severely worn gear rotor oil pump housing wear (Pump is built into the extension housing). Loss of oil pressure will then cause popping out of high range too. Have repaired lots of these transmissions. Input shafts are really hard to find new any more. Bob Hmmm, I think when it's running again I'll film a little video and post it on Youtube. Maybe you and the other knowledgable folks on this forum will better see what I'm talking about. I'm not 100 percent sold on swapping transmissions. I want to be on the road reliably quickly and cheaply as possible. If I can fix it easily I'll try that first before the trans winds up collecting dust. Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted September 19, 2011 Report Share Posted September 19, 2011 (edited) Do all the tests and things Pat stated before tearing into the trans! Make sure the transmission itself is full of oil-I use 20W myself and have even used 10/30 on a iffy trans in a real pile car and it got it to shift fine. But do 10W or whatever oil just to make sure the transmission is full. Fluid coupling is separate and will not cause trans noises or upshift trouble- just slipping on take offs. If after checking wiring/idle speed ect---- if it still bangs and shifts erractically disconnect carefully the wiring (5 wires) from the transmission ,solenoids/governer and interupter sw. ( wiring only controls when it will upshift or downshift) and see if it now shifts fine-note it will upshift the second you let off the gas and will not downshift at a stop unless you push the clutch in and wait 10-30 seconds. Other than these two items and it now shifts fine- electrical issues are most likely the problem. If with the wiring off and it still shifts noisy and poorly the transmission is suspect internally and probably requiring repairs. Bob Edited September 19, 2011 by Dodgeb4ya Quote Link to comment Share on other sites More sharing options...
William Davey Posted September 19, 2011 Report Share Posted September 19, 2011 In the early 60's when I was still a teenager, I swapped out the clunk-o-matic for a junk yard 3 speed in my 1950 DeSoto. Youth and exuberance triumped over ignorance because the car actuall ran and shifted when I was done. HOWEVER, I didn't understand what all the wires were for, so I left them hanging figuring that something would stop working. Off we went on a test drive. After about 10 miles the carburetor had dumped a lot of raw gas (a plunger that prevents stalling?) and the muffler exploded in a giant fireball. Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted September 19, 2011 Report Share Posted September 19, 2011 Three wires go to the M-6 carb- 1) 2 separate wires go to the anti-stall dashpot- a small solenoid thats pulls up a plunger that controls the carb from stalling. If you were to take the plunger out of the carb 95% of the owners wouldn't even know it! 2) 1 or 2 twisted wires-generally one depending on model and production# or build plant location go to the built in carb kick down plunger. Pulling the M-5/6 transwires off and not letting them touch ground or each other is totally proper and safe and will not cause any EXPLOSIONS and fire balls!!! In williams case- being 16, I'm sure one of the wires grounded out and caused the ignition to get shorted on and off and of course the result is the same as turning the key off while coasting the car then key back on and guess what--- one a hell of a explosion- raw unburned fuel in the exhaust system. Also a muffler 2 times the size it's supposed to be! Cut the wires to the carb and you will end up with no capability of a forced throttle downshift and maybe when skidding to a stop from 60MPH the engine might die because of no anti-stall dashpot operation. No fires or explosions- I promise! Bob Quote Link to comment Share on other sites More sharing options...
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