? For Those With Fluid Drive Couplers

[55 Fargo]

Hi , for those driving a Dodge or Desoto, or even a Chrysler, with fluid drive, and 3 speed standard trans.

How much off the line power difference/loss is there or can be noticed, compared to a Plym or Dodge with 3 speed standard and regular clutch.

I ponder every once in a while, whether to convert my 47 back to fluid drive, with 3 speed trans or 3 speed od trans, for originality, and comfort of driving reasons.....

Edited September 26, 2011 by Rockwood

[Adam H P15 D30]

As I never drove my 47 (basket case) and the last old Mopar I had was my 39 Plym with a 201, I don't think my 49 Dodge FD is all that much slower off the line than a non fluid drive vehicle would be. Don't get me wrong, it is slow but it is also a Flathead. Faster than Uncle's 36 Ford (8BA) from 20mph on????? But not that much slower below 20mph. FWIW

[55 Fargo]

As I never drove my 47 (basket case) and the last old Mopar I had was my 39 Plym with a 201, I don't think my 49 Dodge FD is all that much slower off the line than a non fluid drive vehicle would be. Don't get me wrong, it is slow but it is also a Flathead. Faster than Uncle's 36 Ford (8BA) from 20mph on????? But not that much slower below 20mph. FWIW

Thanx Adam, it was sugested, how about a fluid coupler and T5 OD trans, now that would be interesting:cool:, but what about the input shaft:eek:

[Adam H P15 D30]

Need to know an EXCELLENT machinest for that one!!

[busycoupe]

My D24 business coupe has a 3 spd with fluid drive. It is definitely not fast. I have not driven a D24 or P15 with a regular clutch set-up so I really can't say how they compare. I usually start off the line in second gear and it is OK for normal driving. (first gear is very low, probably good for mud or steep hills) It is possible to start off the line in third, but when I do, little kids on tricycles complain that I don't get out of the way fast enough. Once rolling it is very easy to drive and when the fluid coupling is fully engaged, around 20 mph and up, I wouldn't think it would make any difference. It is also very easy on the clutch. When starting out my procedure is 1) depress the clutch and shift into second, 2) release the clutch but hold the car with the brake, 3) release the break and accelerate away. 4) at around 15-25 mph depress the clutch to shift to third. The clutch is not slipped at all.

Dave

[Adam H P15 D30]

My D24 business coupe has a 3 spd with fluid drive. It is definitely not fast. I have not driven a D24 or P15 with a regular clutch set-up so I really can't say how they compare. I usually start off the line in second gear and it is OK for normal driving. (first gear is very low, probably good for mud or steep hills) It is possible to start off the line in third, but when I do, little kids on tricycles complain that I don't get out of the way fast enough. Once rolling it is very easy to drive and when the fluid coupling is fully engaged, around 20 mph and up, I wouldn't think it would make any difference. It is also very easy on the clutch. When starting out my procedure is 1) depress the clutch and shift into second, 2) release the clutch but hold the car with the brake, 3) release the break and accelerate away. 4) at around 15-25 mph depress the clutch to shift to third. The clutch is not slipped at all.

Dave

Does your fluid drive drag the engine down ALOT? I always use it like a non fluid drive clutch because mine really drags the motor down. Almost can hear the rods rattle when leaving a stop if the clutch is not used.

[busycoupe]

My car behaves much like an automatic off the line, perhaps about as quick as an old GM 2 spd auto. The fluid drive does not "drag the motor down". Perhaps your carb accelerator pump need attention.

Dave

[Rusty O'Toole]

Does your fluid drive drag the engine down ALOT? I always use it like a non fluid drive clutch because mine really drags the motor down. Almost can hear the rods rattle when leaving a stop if the clutch is not used.

You should be able to shift into gear and release the clutch fully with the brakes on, or handbrake applied. Then release the brakes and drive off like an automatic. The sensation of pulling away, should be the same as driving a modern automatic.

This is if you are in low or second. If you start off in high should do it without protest but very slow off the line.

If your fluid drive unit is not slipping like an automatic, it could be broken or faulty. They almost never break down or freeze up but I suppose after 60+ years anything can happen.

[Rusty O'Toole]

For the record Tom McCahill tested a 1948 Dodge with Fluid Drive and described it as being on the slow side for a 100HP car.

To put this in perspective the Dodge was a medium price car and more powerful than the typical Chev or Plymouth. But even by the slow standards of the day the Dodge was no ball of fire. McCahill was no fan of automatic transmissions. At that time all automatics were slower than their manual trans counterparts.

[49roadster]

I have a 49 Dodge wayfarer with Fluid Drive and a 49 Plymouth Suburban with out Fluid Drive. I think the dodge with 230 cu. in. has about 10 horses more than the Plymouth 218. The Plymouth is quicker by far.

[Adam H P15 D30]

You should be able to shift into gear and release the clutch fully with the brakes on' date=' or handbrake applied. Then release the brakes and drive off like an automatic. The sensation of pulling away, should be the same as driving a modern automatic.

This is if you are in low or second. If you start off in high should do it without protest but very slow off the line.

If your fluid drive unit is not slipping like an automatic, it could be broken or faulty. They almost never break down or freeze up but I suppose after 60+ years anything can happen.[/quote']

It does disenguage but it feels as if it has about a 600 rpm stall?? Locked up by 1000 rpm? I always thought this is the way it is supposed to be. Maybe the previous owner put the wrong fluid in it?? Thats why I drive it like a non FD. Thoughts???

[greg g]

I learned to drive on my father's 54 meadowbrook with the three speed behind the fluid drive. He and I drove it like a standard, starting in 1st thes shifting through 2nd to high.

I did not notice any slippage in normal driving. He would use 2nd gear and the brake for city driving.

When I drove it at lights, I would put it in first, release the clutch, build a bit of torque against the FD with the brake and gas pedal, and then floor it and release the brake when the light turned green.

It would shoot away from the stop pretty briskly. Not a tire burner, but pretty respectable, It was a lot quicker to 40/45 than my buddies 54 Chevy with the 6 powerglide set up even if he started in low and preloaded the Torque converter.

the 230 was rated at 110 hp in 54, the 235 Stovebolt was rated at 115. The 54 Plymouth was rated at 100 for the 218, and the same 110 for the 230.

I know the Dodge was a lot quicker than another friends DeSoto with the M 6. Keep in mind the Plymouths were quite a bit lighter than the rest of the mopar line even the dodges were about 300 lbs heavier.

Alway thought that learning to drive standard trans with fluid drive was cheating. Great car to take a drivers test on.

[55 Fargo]

Greg, plus the Desoto with the M5 or M6 trans generally had 3.54 diffs, and as you said were and are heavier.

I like the notion of the city driving from lights in 2nd gear, no clutch use, and being authentic to my particular car.

This is just in the idea stages, I have all the items to revert back to FD, but will nto do it with present engine, will wait till I have my 251 ready to go...

[oldodge41]

My '41 Dodge has a '48 230 coupled to fluid drive and three speed. With the original differential (4.11) it was pretty slow off the line. Even worse with the sick 218 I cobbled together when I first got the car running. First gear was pretty much optional in any situation. Now I am running a 3.27 rear differential and I like it better. No race car by any means but more respectable. I can still start in any gear but it prefers first. I have driven a couple old flathead Dodge trucks with three speed transmissions and I believe they were about the same off the line as my old setup but they were probably geared lower yet. I do feel the fluid drive work now if I shift up too soon. Would not want to try these gears without the fluid drive. I think it would eat clutches.

[55 Fargo]

My '41 Dodge has a '48 230 coupled to fluid drive and three speed. With the original differential (4.11) it was pretty slow off the line. Even worse with the sick 218 I cobbled together when I first got the car running. First gear was pretty much optional in any situation. Now I am running a 3.27 rear differential and I like it better. No race car by any means but more respectable. I can still start in any gear but it prefers first. I have driven a couple old flathead Dodge trucks with three speed transmissions and I believe they were about the same off the line as my old setup but they were probably geared lower yet. I do feel the fluid drive work now if I shift up too soon. Would not want to try these gears without the fluid drive. I think it would eat clutches.

I would have thought you would have more jump off the line with the 4.11, than the 3.27, which would give you way more cruising speed.

I think with your present engine, you would be harder on clutches, than the FD set-up. But your car with a hopped up 230 or 251, would no doubt be able to handle it.

I have 3.73 gears in my 47 Chrysler coupe, a car about 600 lbs heavier than a 48 Plym, I havea long block 100 hp flattie, dry cutch and 3spd trans, it moves along okay, but with a fresh 251 it would be much better, with say an addtional 25 hp...

[Rusty O'Toole]

It does disenguage but it feels as if it has about a 600 rpm stall?? Locked up by 1000 rpm? I always thought this is the way it is supposed to be. Maybe the previous owner put the wrong fluid in it?? Thats why I drive it like a non FD. Thoughts???

That sounds about right. You should be able to come up to a stop light, idle down in gear, step on the gas and drive away like an automatic.

Your engine is supposed to idle at 450 RPM and max out at around 3500, much slower than today's engines. So a low stall speed is necessary with your motor.

[55 Fargo]

That sounds about right. You should be able to come up to a stop light' date=' idle down in gear, step on the gas and drive away like an automatic.

Your engine is supposed to idle at 450 RPM and max out at around 3500, much slower than today's engines. So a low stall speed is necessary with your motor.[/quote']

Really even with a fluid drive and 3 spd trans, I thought that was necessary with the M5 or 6 semi-auto trans.

I guess even with the 3 spd you need to idle down , so it is not surging forward while stopped and in gear with clutch out.

[oldodge41]

I believe the FD negated some of that jump because of the inherent slip in the unit. Now I can get up to speed much quicker because I don't shift twice in the first 20 yards and the FD hooks up and allows me to accelerate harder without the slippage it had due to the quicker rpm rise. These motors have the torque to run very relaxed at a very low rpm. I never run much above 60 mph in the old girl anyway but more HP is always a good thing. I would love to have a 25" motor to do a rebuild on and add some bolt on hp parts but due to the distributor to steering box clearance issue (and the fact I don't have a 25" motor) I will probably do a 230 when the time comes. I may experiment with a 3.55 or 3.73 in the future also.

[Adam H P15 D30]

That sounds about right. You should be able to come up to a stop light' date=' idle down in gear, step on the gas and drive away like an automatic.

Your engine is supposed to idle at 450 RPM and max out at around 3500, much slower than today's engines. So a low stall speed is necessary with your motor.[/quote']

Thanks for the clairification. Mine is working properly then...

Thanks again!!!

[DLK]

That sounds about right. You should be able to come up to a stop light' date=' idle down in gear, step on the gas and drive away like an automatic.

Your engine is supposed to idle at 450 RPM and max out at around 3500, much slower than today's engines. So a low stall speed is necessary with your motor.[/quote']

With my Dodge I depress the clutch when stopped even though I wouldn't need to because with a generator it discharges when running at such low RPM and oil pressure drops although never below about 30 lbs. Like others have said I only use first gear when starting out on a steep hill. It is nice being able to start out in 2nd and accelerate with normal traffic.

[JIPJOBXX]

[Frank Ollian]

Do you guys think engines in fluid drive cars are slower revving because of the extra weight of the fluid coupling and fluid?

Frank

[Dan Hiebert]

Isn't the power transfer for the fluid drive in the high 90% range? As in 97 - 98%? 100% would be impossible since there's no mechanical connection. I tend to start in second and shift between second and third most trips, but taking off in first can be pretty lively (for a big car with "only" 100 hp), and taking off in second keeps up well with traffic. Third is another story (yep, them tricylce riding roughians can get rather belligerent), but it impresses those who are not enlightened about fluid drive.

[Merle Coggins]

It's fun to have a new rider in my truck when I let the clutch fly with my foot on the brake and the truck doesn't go until I release the brake and stomp on the gas. I usually drive mine like the 4 speed truck that it is. However, since it has a spur gear 4 speed trans, which means I need to double clutch, I find that I can accelerate just as quickly starting out in 3rd at a traffic light and only have to upshift once, unless it's an uphill grade. It's a little slower off the line but the torque of the engine quickly recovers and makes up for the the time it takes to double clutch upshift.

Merle

[B-Watson]

It does disenguage but it feels as if it has about a 600 rpm stall?? Locked up by 1000 rpm? I always thought this is the way it is supposed to be. Maybe the previous owner put the wrong fluid in it?? Thats why I drive it like a non FD. Thoughts???

There is no lock up of any sort on Fluid Drive. It is a simple fluid coupling, one side throws fluid at the other which makes it turn. And thus it never disengages as there is nothing to disengage.

The faster the engine turns, the faster the fluid coupling turns. It never gets to a 1:1 state and the two vanes are never locked to act as a solid conection between the engine and transmission.

There is a possibility it has the wrong fluid. No harm in changing it.