plymouthfury Posted April 22, 2014 Report Share Posted April 22, 2014 I've recently picked up a '47 DeSoto coupe and a '48 coupe parts car. It appears that my DeSoto is equipped with the semi-auto fluid drive transmission. The shifter does not go into what would be first gear. Also the top cover is removed from the floor and I can see wires and solenoids. Someone put an alternator on the car at some point...and the wiring looks like it could start a fire at any given moment. I havent got the car started yet. But I know the wiring all needs to be ripped out and redone. Would the fluid drive trans work with 12 volts? I tried doing some research but I haven't got any definitive answers. Do the Chrysler/DeSoto flathead 6's have the same bellhousing pattern as the Plymouth/Dodge versions? So one could bolt a standard 3 speed out of a flathead Plymouth/Dodge onto a Chrysler/DeSoto 6? Are flywheels interchangeable between the two? I figure I might would just go that route and swap in a standard 3 speed. I'm guessing some mods to the driveshaft and crossmember might be needed since the whole setup would be shorter? I guess a 3spd OD would be another option. Thanks Quote Link to comment Share on other sites More sharing options...
William Davey Posted April 22, 2014 Report Share Posted April 22, 2014 My 2nd car was a 1950 Desoto. The transmission has 2 ranges, low range (1st and 2nd gear) is where 2nd gear would be on a 3 speed. High range (3rd and 4th gear) is where 3rd would be on a 3 speed. Normal operation is to put it in high range, let out the clutch and step on the gas to accelerate to about 25 mph - let up on the gas and the trans will "click" into 4th gear and you're done. However, the transmission in mine was shot (maybe just not adjusted right), but I was convinced it needed replaced. Put in a 3 speed out of an early 60's Dodge pickup and it bolted right in using the original flywheel, fluid drive and clutch. In my youthful exuberance, I figured the extra wires (not needed by the 3 speed) were for backup lights - wrong! Actually were for a solenoid that pumps extra fuel into the engine between shifts to prevent stalling. With the wires unhooked, the solenoid was dumping a ton of extra fuel into the engine. I discovered this when the muffler EXPLODED about 5 miles into my first test drive. So to answer your question: yes a 3 speed can be made to work behind the fluid drive and clutch, but why don't you try to get the original trans working first. There are lots of references on this forum and also on the Imperial Owner's forum. Quote Link to comment Share on other sites More sharing options...
Don Coatney Posted April 22, 2014 Report Share Posted April 22, 2014 Was there a difference in the length of the transmission input shafts between the standard non fluid drive coupled 3 speed and the original Desoto transmission? Suggest you read the information at Allpar linked below. http://www.allpar.com/mopar/fluidrive.html The only basic difference in the pre-1950s transmissions, between the fluid drives and non fluid drives, is the length of the input shaft Quote Link to comment Share on other sites More sharing options...
plymouthfury Posted April 22, 2014 Author Report Share Posted April 22, 2014 I've read up on the fluid drives. I haven't looked into the wiring schematic yet. But will running 12 volts have any negative effect on the solenoids and whatnot associated with the fluid drive? I can't seem to find anyone that says Yes. or No. with 100% certainty! I plan on trying to get the car drivable with the original drivetrain first and see if the thing works. But I have to rewire the car before I can even attempt that. The wiring is a MESS. What I was wondering is if the fluid drive can be eliminated completely and just a standard clutch used? Basically using the whole setup out of a Plymouth for example. And if running 12 volts makes any difference. Quote Link to comment Share on other sites More sharing options...
Dodgeb4ya Posted April 22, 2014 Report Share Posted April 22, 2014 (edited) You really should own a factory 1949-1950 Chrysler shop manual so you can understand everything about your C48 Windsor. I keep all my M5/M6 chrysler cars stock 6 volt as they always work fine so I cannot help you about a 12V modification. Here is the proper wiring diagram for the Dodge DeSoto and Chrysler M6 wiring....... Bob Edited April 22, 2014 by Dodgeb4ya Quote Link to comment Share on other sites More sharing options...
William Davey Posted April 23, 2014 Report Share Posted April 23, 2014 Don, If you're asking about the swap I did on the 50 Desoto? I don't remember many of the details of the swap, but do recall installing the differential out of the same truck. Biggest problem with the swap was bending the shift rods to work and the EXPLOSION noted above. This was all done in my Grandfather's garage by 3 teenagers in 1964. Quote Link to comment Share on other sites More sharing options...
plymouthfury Posted April 24, 2014 Author Report Share Posted April 24, 2014 I looked over the car today and compared it with the parts car. The carb is not the original type. The wiring harness was totally bypassed and a hole punched in the firewall for some newer wiring. The wiring is total garbage and is nearly impossible to follow. I'm not even sure if the car was ever really drivable. Some people should not ever mess with cars. Now I got to just rip everything out and redo all the wiring and other things. I think I will look into putting in a standard 3 speed in place of the fluid drive. Quote Link to comment Share on other sites More sharing options...
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