"fluid drive" manual Tranny

[Blue88Comanche]

I sound a web page that has some info on "fluid Drive" manual transmissions.. ...I thought it was neat idea.. I wonder how well it would work for rock crawlers, I have heard that a auto tranny is better for that sorta thing..

 

"Chrysler’s first fluid drive cars were introduced in 1939. They were equipped with a standard 3-speed manual transmission and clutch, but had a fluid coupling in place of the conventional flywheel. This set-up was available on all Chrysler models from 1940 through 1948, and on DeSoto and Dodge models from 1941 through 1946, at a slight extra cost. From 1947 through 1952, the fluid coupling/3-speed manual transmission combination was standard equipment on all Dodge models and optional on DeSotos. In 1953-54, Plymouth offered a variant called “HyDrive”, which is a 3-speed manual unit and clutch, with the fluid coupling updated to a modern torque converter (pictured above right).

 

These cars do not change gears “automatically,” but can be held stationary in any gear without disengaging the clutch. They can also be started in any gear without slipping the clutch, although 3rd gear starts are painfully slow. Fluid drive advantages are:

 

1. The car can be driven by declutching and shifting in the normal fashion, starting in 1st, shifting to 2nd, and then to 3rd.

2. Downshifts from 3rd to 2nd are greatly reduced.

3. In stop-and-go traffic, the car may be left in 2nd gear with the driver starting and stopping merely by applying the foot brake and accelerator pedals, as is done in a car equipped with a modern automatic transmission.

4. Acceleration from 5 MPH up in 3rd gear is entirely acceptable under most level-road conditions.

5. Ascending moderately steep hills does not require downshifting.

6. 1941 DeSoto with Fluid DriveUnder light loads and relatively flat road conditions, the car may be started from rest in 2nd gear with entirely satisfactory acceleration results and without putting any strain on driveline/clutch parts.

7. Starting on hills is greatly facilitated. The car may be placed in 1st gear, the clutch engaged, and the car held motionless by application of the foot brake only. When it is time to start, the driver merely steps on the accelerator. There is no need to coordinate the clutch/brake/accelerator with the inevitable engine over-revving and clutch slipping that are the hallmark of manual-shift car hill starts.

8. Wear on clutch parts is greatly reduced because there is no need to “slip” the clutch for smooth starts from rest.

9. Fluid drive cars have a lower numerical rear axle ratio, thereby reducing constant speed engine RPMs.

 

There are also disadvantages:

 

1. When starting from rest in 1st gear, “off the line” acceleration suffers because of the “slipping” action of the fluid coupling. This is largely overcome at the point where the car attains a speed of 10-15 MPH, however.

2. Leaving the transmission in gear with the engine off does not lock the rear wheels. A fluid coupling car left in gear with the engine off will roll just as if it were left in neutral. Therefore, maintaining the emergency/parking brake is paramount, and care should be taken when parking the car when anything but absolutely level road conditions are encountered."

 

From: http://www.allpar.com/mopar/fluidrive.html

[dasbulliwagen]

Sounds a lot like the old VW autostick. It had a 3 speed manual, a vacuum actuated clutch, and a torque converter. I had one in a 1972 Karmann Ghia I once owned. I can't see any manufacturers making one ever again due to its lack of efficiency. Most maufacturers are currently doing away with the CVT trannys as well for the same reason. Most now are going to a dual dry clutch system, that uses a small hydraulic circuit to actuate two clutches back and forth to change gears. You have an even gears clutch, and an odd gears clutch, and an electronic gear selector. These build less heat than an auto, and MUCH less heat that a CVT.