In 1954, Chrysler finally had an automatic transmission, after years of manuals and semi-automatics — and just in time, too, as the average driver was now demanding one.
The new Powerflite was, like early Ford and GM automatics, a simple two-speed affair, combining a torque converter and a two-speed planetary gearbox. The company bragged that it was “100 pounds lighter than the heaviest competitive unit, and contains 110 fewer parts than the most complicated of these.” (Note they did not benchmark the best, but the worst. They would make up for this with the TorqueFlite, later.)
Neutral and drive were on one level of the selector level; reverse and low gears, on a higher level, were selected by lifting a lever and sliding it left or right. The setup was like the later PRNDL (Park, Reverse, Neutral, Drive, Low), but without a Park setting.
In 1960, Chrysler wrote that the car had to be started in Neutral; and if the car was moving at 10 mph or more, Reverse would drop the car into Neutral, also for safety. Likewise, the low gear or 1 button would be ignored if the speed was already too high.
This section contributed by Lanny Knutson, and transcribed by David Hoffman.
The engineers had done their homework well; it started in low, unlike some Fordomatics, shifting into high at eleven miles per hour. It could also be manually held in low, and the car could be push started without any damage. It did not, though, have a Park position or a lock-up in Reverse, making an effectively parking brake necessary. For that reason, the parking brake was changed to an internal-expanding unit mounted on the transmission tail shaft, as was the external-contracting brake on the manual gear box.
Not much credit is given to the Powerflite transmission, probably because it was overshadowed by the absolute best automatic transmission ever built, the Chrysler Torqueflite. Yet, the Powerflite soldiered on into the 1961 model year, a seven year run. It was a simple transmission built around a planetary gear set, not unlike the early Model T Ford; it was also very strong, and it was simple, with fewer parts than its competition from Ford, GM, Studebaker, or Packard.
In one of its strangest applications, the Los Angeles Police equipped its 1960 Plymouth Savoy fleet (330 units) with a 318 cubic inch V-8 and the Powerflite transmission (along with 303 similar Dodge Darts). The vastly superior Torqueflite had been around for three full years, and was king of the fleet buyer’s specifications — but the LAPD specified that the transmission had to share the oil with the engine!
It was an odd demand, and only Chrysler was able to meet the specification, virtually without any changes to the transmission. Both Chevrolet’s Powerglide and Ford’s 2 speed Fordamatic destroyed themselves within a few hundred miles with 20 weight engine grade oil. The Powerflite and later Torqueflite soldiered on like nothing happened.
The Powerflite was discontinued after 1961 (the Hy-Drive only had about one year).
In 1955, the Powerflite automatic was given an unusual dash-mounted lever, later common in minivans. In 1956, the pushbutton automatic was introduced with the Torqueflite automatic, continuing experimentation with new ways to change gears.
At least one owner complained about the gear ratios with the Powerflite, which reduced acceleration compared with the manual gearbox.
Mike Peterson wrote in the Walter P. Chrysler Club magazine:
The 6 cylinder and V8 transmissions in 1955 were all the same except the clutches. 1955 was the only year for the automatic transmission lever mounted on the dash, although Corvair used that location for a while.
The PowerFlite transmission is air-cooled, as is the torque converter. The absence of a vacuum modulator enhances the simplicity of this unit.
One of the idiosyncracies of the design is a very high (260 lb/sq.in.) fluid pressure when the transmission is in reverse. The life of the PowerFlite can be extended by first shifting to drive (foot on the brake) to cut the engine idle speed before going into reverse. During a rebuild, transmission life will also be extended by installing the kick-down cushion spring in the trash can, not in the PowerFlite. This spring softens the shift by momentarily holding the transmission in low and drive during kick-down, and puts a severe strain on the internal components.
One of the nice things about the PowerFlite is that it comes with the four pinion rear axle. The four pinion unit is the stronger of the two offered in 1955 and, when coupled to the PowerFlite, will last forever and a day. In 1956 the four pinion axles were high performance options. 3.54 is a standard rear gear with the PowerFlite, 3.73 is an optional ratio. Manual transmission sixes got 3.9, 4.3 with overdrive; the V8 counterparts received 3.73, 4.1 with overdrive. These are the two pinion units and do not appear to be as strong as the four pinion units.
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Click here for a page on the Hy-Drive transmission.
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