Fluid Drive Transmission

Started by tonto1, July 17, 2009, 02:01:56 PM

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tonto1

Hi;
I'm looking at a '49 Dodge that has the Fluid Drive transmission.
Is anyone here familiar with them.
Are they nothing more than a standard transmission with a clutch that can slip when you come to a stop?
Why are there more horses a**es in the world than there are horses?

Carnut

Quote from: "tonto1"Hi;
I'm looking at a '49 Dodge that has the Fluid Drive transmission.
Is anyone here familiar with them.
Are they nothing more than a standard transmission with a clutch that can slip when you come to a stop?

Well, I learned to drive in a 48 DeSoto with a fluiddrive transmission, so guess I know a little about using them.

Not sure what all is inside them.

Yes it has a clutch and a torque converter.

On mine I remember being able to only shift between two gears on the column, think if I remember correctly on an H pattern it was second and third locations with no location for first gear.

So I would start out in with shifter in 2nd location drive a bit up to speed and lift on the gas and the transmission would shift automatically to what seemed to be another gear. Then I would run it up a bit more and shift to 3rd and drive up to a bit faster speed and then let up on the gas and it would automatically shift to what seemed to be another gear.

Thus it 'seemed' to be a 4spd semi auto trans.

Back 'in the day' my mother drove the car without ever using the clutch and if I recall correctly she only put the car in 3rd to go forward and never shifted.

About the worst thing with these early mopars is forgetting to release the hand brake and then driving down the road trailing a cloud of white smoke out from under the car until you realized you forgot the 'handbrake'.

tonto1

Yes, my brother-in-law had one when he was dating my sister, which was back in the 50's, and I thought that was I remembered it being.
The fellow that owns this car says it has 3 regular gears forward and it doesn't upshift.
I wonder if they had more than one transmission?
Why are there more horses a**es in the world than there are horses?

enjenjo

Basically it was a three speed stick, with a fluid coupling in front of the clutch. Yo9u could shift them manually, but it didn't gain much because of all the slippage. The fluid coupling did no torque multiplication, so technically it is not a torque convertor. All that was in one was a pump, and a driven member, no stator.
Welcome to hell. Here's your accordion.

kb426

I drove one of the 48-9 pickups in the sandhills when I was young. Flathead 4 cyl. That thing didn't have enough power to do anything. It wouldn't untrack by flooring it so I'd drop the clutch at low rpm. If it spun the tire a half turn I was stuck and walking towards a tractor. Not my best memories. I always used the clutch to shift gears but can't say I didn't need to. I wasn't brave enough to find out.
TEAM SMART

Carnut

Quote from: "tonto1"Yes, my brother-in-law had one when he was dating my sister, which was back in the 50's, and I thought that was I remembered it being.
The fellow that owns this car says it has 3 regular gears forward and it doesn't upshift.
I wonder if they had more than one transmission?

Ok, it seems there were different versions according to wikipedia,

QuoteFluid Drive is the trademarked name that Chrysler Corporation assigned to a transmission driveline combination offered from 1939 through 1953 in Chryslers, 1940 through 1953 in Desotos, and from 1941 through 1954 in Dodge models. The fluid drive element was a hydraulic coupling inserted in place of the flywheel, and performed the same function as a modern torque converter, only without torque multiplication. A conventional clutch and three-speed manual transmission was installed behind the fluid coupling, although a semi-automatic was optional from 1941 for Chrysler and DeSoto and from 1949 for Dodge.

QuoteFluid Drive could also be mated to the semi-automatic transmission, which was not automatic in any way and should not be confused with Fluid Drive. With the semi-automatic transmissions, the driver shifted manually, selecting reverse or a low range and a high range. Each 'range' had two speeds. To shift between them, the driver accelerated then released pressure on the accelerator. In high range this shift point was about 23mph (37kmh). The transmission shifted into high speed range, the driver then depressed the accelerator pedal, and continued accelerating. The solenoids on the transmission connected to the carburetor and ignition system and momentarily interrupted engine operation to allow trouble free shifting.

QuoteThe driver could down-shift for passing by fully depressing the accelerator. The clutch was needed to change between low and high range. The fluid drive system allowed the driver to stop at a light or in traffic and remain in gear without depressing the clutch. The driver could, if not concerned with fast acceleration, drive the car all day long in high range, stopping and starting, without ever having to touch the clutch pedal or gearshift lever unless faster acceleration or reversing was required. For this reason DeSotos and Dodges were favored by city cab companies from the mid Forties to early Fifties.

http://en.wikipedia.org/wiki/Fluid_Drive

Bet the DeSoto I drove had the semi-automatic version instead of a the straight 3spd stick.

GPster

If you are lucky enough to find the parts you can bolt together a standard shift set-up in that chassis. I was playing around with a '47 DeSoto that used the long bellhousing but it had a standard transmission behind it. The fluid drive transmission input shaft is long enough to reach through the fluid coupling but it is smooth on the outside for the first 4 or 5 inches then it has splines of the clutch on it. The throw out bearing and the collar that it rides on on the front of the fluid drive transmission look like regular standard transmission pieces because the thickness of the fluid drive on the end of the engines crankshaft puts the clutch assembly a normal distance from the transmission case. The stand shift transmission for the long bellhousing has an input shaft that is probably over a foot long and the splines for the clutch are right behind the surface for the pilot bearing (that is probably 3/4" in diameter and about 1 1/2" long). The throw-out bearing is probably about 8" long and the collar for it on the front of the transmission is also long to suite it's purpose. The starter ring gear for the fluid drive set-up is on the fluid drive and I'd think it's in the same place in relation to the back of the engine that a standard shift flywheel's ring gear would be. Like I said I found most of this in the DeSoto parts probably because a lot of DeSotos were planned to end up with fluid drives so they would need the long bellhousing. The back motor mounts of Chrysler Products of this era were on the bellhousing and these mount stands were welded to the frame. If the vehicle was to be standard transmission and use the short bellhousing it would have to have a frame with the mount  stands in a different place so they'd need to have two frames. They probably thought it was easier to have two sets of bolt-on pieces than to have two different welded assemblies. Now I'll throw in some other things that I have found with no rhyme or reason just so you know it could be. I've heard it said that some of those fluid drives have engine oil in them and I know that some of them are sealed with their own oil in them and a plug that can be removed to check and/or change the oil. If it runs on engine oil than I would expect a seal and an oil gallery between the engine crank and the fluid drive. If you were interest in standar shift enough to read all this dribble I have found the back of some Chrysler engine crankshafts that were put against automatic transmission applications that the fifnsh machining of the crank for a pilot bearing was not done. Just something to read because it certainly has been quiet here lately. GPster

tonto1

Thanks for all the info.
I suspected what you said was true if all the iformation I got was true.
The Dodge was a low line car and only got the torque converter in front of the pretty much standard 3 speed, wereas the more expensive cars had a torque converter hooked to a semi-automatic transmission
Again, thanks. I was interesting reading.
If I buy the car, I'll probably leave it as it is.
Why are there more horses a**es in the world than there are horses?