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How to drive a FLUID DRIVE equipped car

One of the questions we get asked frequently here at ABAP is HOW to drive the Fluid Drive equipped cars. We understand the confusion as the Fluid Drive equipped cars don’t drive like a standard shift, don’t drive like a modern automatic, and to make it all more confusing, different cars in the Chrysler line up were operated differently, and the different car lines used different “brand names” for their Fluid Drive set ups! What could possibly go wrong!

First a little background

Driving a fluid drive equipped carChrysler Corp rolled out the FLUID DRIVE coupling on 1939 Chryslers. In these early cars the Fluid Drive coupling replaced a conventional flywheel. There was no SEMI AUTOMATIC TRANSMISSION on these cars, so no automatic shifting of any kind. BUT the fluid drive coupling allowed you to stop at a stop sign in second gear and NOT depress the clutch. Very cool and very advanced for 1939! This simple mating of a fluid drive coupling with a standard transmission was used on Chrysler for 1939 and 1940, on Desoto 1940, and Dodge until 1949.No automatic shift from gear to gear, but no need to depress the clutch at stop signs, as long as you are in second gear. Fluid drive coupling means you can idle in second gear without pushing in the clutch…like a modern automatic!



NEXT step was the semi- automatic transmissions…rolled out in 1941 for Chrysler and Desoto and then in 1949 for Dodge. We won’t deal with the differences in the post and pre -war transmissions here ( pre -war: vacuum operated, post war hydraulic operated) let’s just concentrate on how to DRIVE them!

TO START FROM A DEAD STOP in a post-1941 Chrysler or DeSoto Fluid Drive Equipped Car:

Use the clutch to put the car in HIGH range…that is gearshift towards the dashboard and DOWN. Start off like a normal “standard” trans car…when the car reaches about 14 MPH let off the gas…and the car will shift AUTOMATICALLY into “high gear.” No clutch needed. You’ll hear a bit of a “click” when the transmission makes that shift. Don’t expect it to shift as quickly as a modern car...you have to wait a second or two for it to make the gear change. When you stop, or slow below 14 mph, the car will AUTOMATICALLY shift into “low”. You’ll hear that shift too. Again, no clutch needed!

Once you are off and running, you should be able to drive ALL DAY LONG without touching the clutch.

If you want to start with rapid acceleration, or are going up hill, you can choose to start off in “LOW RANGE”…that is gearshift towards the dashboard and UP. IN this range the car will shift from low to high (and back again) at 4 mph…it’s really a “stump puller” range.

To get out of low range and go to high range USE THE CLUTCH and pull the gearshift lever down. Or visa versa to down shift into low range.

One more thing: for a rapid burst of power in high gear (either low or high range) FLOOR the accelerator and the transmission will automatically down shift to the lower gear…again no clutch needed.

So use the clutch to START OFF…to go from LOW RANGE to HIGH RANGE….and to engage reverse ( towards you and up,) Beyond that you can run all day long without clutch!

I drive my 1948 Chrylser New Yorker to work a lot during the nice weather, and with all the traffic lights and stop signs I go through that fluid drive with semi- automatic trans really makes it a relaxing trip!

I guess the only downside: if you leave the car with ANYONE else who needs to drive it you need to explain to them that it is NOT A STANDARD THREE ON THE TREE transmission!

Don’t hesitate to call us if you want to talk about driving (or fixing) your fluid drive equipped Chrysler, Dodge or DeSoto. There is a LOT more to tell on the topic.

To Learn More About Your Fluid Drive and Hydraulic Semi Automatic Transmissions.

IF YOU WANT TO LEARN MORE ABOUT YOUR FLUID DRIVE AND HYDRAULIC SEMI AUTOMATIC TRANSMISSIONS CHECK OUT THESE LINKS TO CHRYSLER MASTER SERVICE BULLETINS CIRCA 1948, COURTESY OF THE ON LINE IMPERIAL CLUB:

Here is the link to “DIAGNOSING THE HYDRAULIC SEMI AUTOMOTIC TRANSMISSION:”

http://www.imperialclub.com/Repair/Lit/Master/012B/cover.htm

Here is the link to “THE HYDRAULIC TRANSMISSION AND HOW IT WORKS:”

http://www.imperialclub.com/Repair/Lit/Master/012A/cover.htm

Hope you find this all helpful, and remember if you get confused or have ANY questions give us a call at 617-244-1118 we can help!

Happy MoPar motoring!

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