I have been reading a book that details the way cars achanged in the 70's....it breifly mentions a late 70's phenomenon in which manual transmissions were installed with torque converters instead of clutches, creating a "clutchless automatic"....is there anyway this could be reproduced junk yard style????

I'm not aware of any semi-automatics in the 70's, but in the late 40's and early 50's, Chrysler had a couple of versions. From my experience with them, I wouldn't waste my time trying to duplicate such an inefficient design. If you could incorporate a lock-up converter, they would work better, but they slipped terribly bad.

FWIW, I'm told Chrysler is currently working on a clutchless manual transmission. I seem to recall hearing that one of the latest concept cars had the feature.

the 70's occurance i was reading of may not have been form mother mopar.....i'll re-research the subject.
the only reaosn i asked was becuase I figured the major compnents are all the same accross the baord.

The manual trans with a convertor instead of a clutch is a '90s creation. There are 2 available, the BRT and Lencodrive units.
You may have read about the 'ClutchFlite' or 'ClutchTurbo' used in the '60s and early '70s. It used a Mopar 727 or GM Turbo 400 automatic trans with a clutch instead of a convertor. They fell out of use with the advent of the Lenco planetary trans.

Cecil

The only semi-automatic trans I have heard of in the 70s was the VW Beetle "Automatic Stickshift" that began in '68 I believe. Basically it combined the sliplosses of a converter with the chores of shifting gears. I dont know why you would want it. Powershift transmissions are used in heavy trucks and equipment all the time; Im sure that some transmission valve bodies could be adapted to operate this way with a chunk of billet and a whole lot of CNC work. But in a passenger car, seeing mostly street use... I dont see the cost/benefit ratio being close to sane...

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

ok...well....my question was only if achieving such a set up would be as easy as slappin a torque converter onto a 4 speed and your ready to go....but thanks.
For your information though the occurance I heard first about was available in 1971 from the general. It was called the "Torque Drive Semi Automatic"....they put it in the Vega 2300.

About the closest I think you could get to that would be a multiple wet disk clutch.

It would require its own hydraulic system, and could be actuated with an electric proportional valve. It is possible that a dimensionally approximate clutch does exist in the forklift industry, or as an accessory drive clutch on very large machinery, like a modern transit bus air conditioning compressor. The TOWMOTOR in our shop uses one, and has a master cylinder to disengage it. You would certainly have to fabricate a custom input shaft, bellhousing, flywheel, crank adaptor plate, we're talking thousands here, and your first gear launch would be bone jarring.

I imagine though, that your intent is to be able to change gears without depressing a clutch pedal. You just cant do this the way manual gearboxes are designed. Basically a semi automatic transmission is an auto trans with individually selectable forward gears. Also known as, a powershift. It's much more feasible to start with an auto trans, and reverse engineer the valve body to give you individually selectable gears, than to start with a manual gearbox. In order to move from one gear to the next, you either have to interrupt power from the engine, or you have to mesh all gears together at once and put clutches on each one, so you can overlap the engagement. It's the only way to match input shaft speed with output shaft speed so the gears dont grind.

FWIW, I have driven graders and scrapers with powershift trannies, and theyre just as much fun to drive as their stickshift counterparts. And a lot easier on the leg, when you have so many forward gears

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

Just a rumor I heard: take a auto stick trans from a 98-2000 Dodge or chrysler FWD Intrepid, Concord, 300M and reorient it north and south, any truth to it being just a 904 pointed in the wrong direction?

A friend of mine has a drag car that is running a 400 turbo and he has an aftermarket setup and it has a clutch for leaving the line and then it is strictly an auto.

Just guessing here, but I believe that setup is basically a main line pressure dump valve, that allows you to rev the engine in drive, and when you let go of the control (button, pedal etc) the circuit closes and main pressure returns to normal. Forklifts use what is called an "inching valve" usually cable operated by a second brake pedal, which does the same thing. Modern variants of this use a pintle valve rather than a spool, which allows easier feathering for more controlled drive engagement. Much more convenient than grabbing the column shifter and moving it between neutral and drive.

You could use almost anything to control an inching valve. Ive always thought it would be neat to hook one to your brake pedal, so it declutches your trans whenever you hit the pedal. It would make me feel better about valet parking for one thing, and in traffic jams I could ride the brake all day without the converter getting hot from all that vortex flow, and probably save fuel and engine wear.

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

I have a '47 DeSoto with a four speed semi-automatic with a Fluid Drive.
FD was a two piece torque coupler was did not offer any torque multiplication. These semi-auto transmissions could probably be greatler improved with a late model lock-up torque converter.

An advantage of F/D was most of the Mopars so equipped never required a clutch replacement. But, they slipped badly until they locked up. Yet, my 236 inline six will chirp the tires when you drop the clutch. Don't confuse the F/D with the modern 3 element torque convertor. This '47 transmission is a convention sliding gear unit that is very similar to a manual transmission, it is hydraulically shifted with solenoids that open the valves.

Could you elaborate on how the gearbox works?

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I've been calling it as i see it for my entire life and that's not about to change. Take it or leave it.

The Mopar semi-automatic was first used in about 1940 in Imperials. It is a two-speed transmission with a high and low range. The innards are nothing special. It has a gerotor oil pump that is similar to the pump in the car's motor. A governor senses the shift speed, about 12-14 MPH road speed, this controls a solenoid which opens a valve allowing oil pressure to slide the gears. The shift mechanism is internal. The early versions were vacuum shifted, the hydrualically shifted M6 is the version that I have, in DeSoto this was called Tip-Toe (because you can't shift under throttle). In the early '50s Dodge had a version called Gyromatic.

You let up on the throttle and wait for the transmission to shift, a spark arrestor cuts out the motor during the gear change. I believe there is also an overrunning clutch in the tranny. These units are typically very reliable. A 2-piece fuid coupler allows clutch less driving, you still use the clutch pedal to change gears to back up. They're filled with 10 wt oil, which I got at Wal-Mart. There is an access panel on the transmission tunnel in the interior of the car.

There is also a Fluid Drive that is basically a 3 speed manual with the same type of 2-piece fluid coupler, throughout the forties this was not available in Plymouths. Plymouths got a Hy-Drive that had a torque converter, but required the oil to be shared with the motor (the heat assisted in smoother shifting during warmup). The troublesome Hy-Drive was quickly replaced by Power-Flite. The Hy-Drive cars had modifications to the floor pan and firewall that make them different from other Plymouths, an overall poor design.