Fluid Drive expectations

[Guest india76pd]

I'm new to this, so please be patient.

After several motorcycle restorations I'm trying a car and have a late '48 Dodge Club Coupe with Fluid Drive. It is undergoing a re-restoration. My question is about the Fluid Drive. What is the comfortable highway crusing speed I might expect? I know this is car is almost 60 years old and I don't expect to set any land speed records. I'm just curious what is reasonable for this car.

Shawn

[Dwight Pectol]

I have a '48 Dodge business coupe with fluid drive and cruse at 65 mph with no problem at all, and have had it up to 80. Good luck with your new project. DW

[Merle Coggins]

What were your motorcycle restoration projects?

[bob westphal]

We drive a restored '47 DeSoto with fluid drive. The rpm seems to be rather high as you accelerate but when you reach 60-65 mph it smooths out and cruises very nicely and and quite comfortabley. A nice smooth ride for a 60+ year old design!

[greg g]

Fluid drive is not the issue highway driving crusising speed wise as is the final drive ratio. The fluid drive is basically a 1 to 1 fluid torque transfer media. Most of these old MOPARS have rearends with high nimerical ratios. My 46 Plymouth has a 4.1 to 1, some were equipped with 3.9 to 1's and a few were blessed with a 3.7 something to 1 deal. I dirive my car at an indicated 62 to 65 on the highway, and compared to a modern vehicle, The engine does sound very busy at that speed. Most of the time I will dirve state or local highways rather thant he interstates when those are available. Remember the interstate highway system was just a gleam in Eisenhower's eye when our car were built, and the average speed on a trip was probably 45 to 50 MPH. So the gearing reflected this type and speed of driving. You just didn't jump on the superslab and drive 70 MPH for 4 hours. So if the fluid drive is in good condition is should not be the limiting factor.

[Guest india76pd]

I feel better about my car now. I was considering an engine/transmission swap, but with this feed back, I'll be happy with keeping it original!

Shawn

[De Soto Frank]

Shawn,

Most of the time, MoPars equipped with the Fluid Coupling were also equipped with slightly taller gears than their "dry-clutch" counterparts...

Not sure about D-24's , but Chrysler & De Soto with FD usually had gears in the 3.54 to 3.73 / 3.90 range; the "dry-clutch" cars usually had 4.1 to 4.3 rears and sound really busy at 60 mph.

The Fluid Coupling allowed enough "slippage" to tolerate a taller ring & pinion.

I would suggest going over your brakes and tires, getting the car roadworthy and driving it some before planning any major mods...

If you think you need taller gears for highway cruising, you could swap in a different rear from a later MoPar or add an Overdrive tranny...

Good luck !

De Soto Frank

[JIPJOBXX]

I think these old cars were made to run all day long at around 55 mph and I do feel that my engine is straining after that. but I have a 42 dodge maybe the engine is a bit smaller. Jon

PS. That is why I bought my 60 T-bird to keep up with the freeway speeds

http://i2.photobucket.com/albums/y4/1942dodge/RichardandTBird005.jpg

[captden29]

i just completed an 800 mile trip with my 54 windsor. i cruised at 55 to 60 all day, closer to 55 most of the time. i have the powerflite, but the real issue is not the tranny but the condition of the drivetrain[brakes too]. if all is well hiway speed is no problem. my convertible[also a 54 windsor] did a 400 mile trip earlier this year and it easily cruised at 60 and above. remember, they are cars, drive them and they are more fun to own. dennis

[hotrodbob]

Tell me if I'm wrong here, but wasn't the trans the same as a regular 3 speed, but coupled to a torque converter with a dry clutch?

That's what my 51 Dodge looked like to me way back when I was in high school

[greg g]

The basic Dodge system is as you described. Chrysler complicated the issue by refering to other systems including the semi automatic as fluid drive also. and then in 49 or so Dodge also offered the Semi auto matic as Gyromatic and continued to refer to is as a Fluid drive system. But the Basic Dodge and Desoto Fluid drive systems had a fluid coupling (not a torque converter) transferring rotations from the engine to the flywheel to which a standard three speed with clutch was attached. Once a gear was selected it could be driven without utilizing the clutch, by driving around in the selected gear using only the gas pedal and brake. Or again to confuse things, you could drive it like a regular three speed car also.