Hi Cory, I repost this again from a few years back as it might be somewhat helpful...
The Unimatic transmission was designed and built by a Frigidaire engineer named Kenneth O'Sissen back in the late 1930's. Kenneth, who was hired by Frigidaire after working at Bendix where he invented the incrementing timer for their bolt-down washer and Kenneth’s basic timer design is still used today in some washers and dishwashers. His Unimatic, (Uni. meaning one and Matic short for automatic) consisted of a pulsator crankshaft & spin cage/brake assembly type transmission located on the top, a motor mounted in the middle and a water pump mounted underneath the motor. It was one complete direct drive unit without any clutches, drive belts or pulleys. The motor ran at 1140rpm, the gearing ratio in the pulsator part of the mechanism made the agitator go up and down in a 1 7/8” stroke at 330 pulses per minute. Since there was no gearing in the spin section of the mechanism, the tub spun at the same rate as the motor -- 1140rpm, which made for incredibly dry clothes. Because of the war effort it wasn’t until 1947 that Frigidaire introduced this mechanism in its very first washer, model WJ-60. Unimatic washers for domestic use were continued to be produced through 1958.
In 1955 Frigidaire engineers experimented with a belt-drive mechanism and introduced the Pulsa-Matic mechanism on its lower end washer model WV-35. The Pulsa-Matic agitated up and down at a very rapid 630ppm and also spun the tub at 630rpm, which was the slowest spinning full-size washer GM Frigidaire ever produced. Because of the rapid agitation with the Pulsa-Matic, Frigidaire shortened the length of the stroke of the agitation from 1 7/8" to 3/4". This change in agitation stroke and pulse rate did reduce the rate of turnover of the clothes which made for less tangling, but did not clean anywhere near as well as the Unimatic’s agitation. For this reason the Pulsa-Matic only lasted 4 years as they continued to market it in '56, '57 and '58. These models (WV-35, WS-56, WD-56, WS-57, WD-57, WS-58, WD-58 and WDP-58) are now some of the rarest of the Frigidaire washers and I only know of one collector that has one of these Pulsa-Matic washers.
The only major design of the Unimatic washers outside of the normal yearly changes in the cabinet and control panels was the introduction of the 3-Ring Agitator in 1956, with a neoprene rubber, gray colored cap, lint-chaser ring and circulator ring. The same colors were used in ’57 and a bleach cup was added. In ’58 Frigidaire’s advertising firm suggested that they color the rings (sort of like they did in the ’57 magazine ad’s), so the cap became turquoise, the lint chaser ring became yellow and the circulator became a coral color.
In 1959 Frigidaire introduced their first coin-operated washer (model WCOZ). The WCOZ used the Unimatic tranny and coin-op Unimatics were produced until 1964. Starting in 1965 Frigidaire introduced other coin-op machines with various mechanisms and continued to make them until the mid 70’s. About 1962 Frigidaire introduce their top-loading Dry-Cleaner, it too used the Unimatic mechanism and I'm not sure how long it was produced for (anyone out there know????).
For the new 1959 domestic washer line Frigidaire discontinued the Unimatic (for home use) and completely discontinued the Pulsa-Matic. They now introduced the Multi-Matic which was nothing more than a very advanced version of the Pulsa-Matic. It consisted of two drive belts (one for agitate and one for spin), a new two speed motor and a special clutch to shift drive power between the two belts. This arrangement produced Frigidaire's first multi-speed washer, allowing for 330ppm for normal wash speed or a 220ppm delicate speed as well as a 850rpm high spin speed and a 330rpm delicate spin speed. Because of the slower 330ppm Frigidaire was now able to return the agitator stroke back to a full 1.25" just like the old Unimatic. For the 1963 line Frigidaire introduced it's new 12lb capacity tub, but unfortunately for both the 1963 and 1964 line Frigidaire cheapened the clutch design of the Multi-Matic which dropped the high spin speed from 850 all the way down to 710.
In 1965 (actually it was the end of the year 1964) Frigidaire introduced the Roller-Matic mechanism. This was now a belt-less mechanism again with rollers of different sizes to drive the transmission. They also brought back the high speed spin of 1010rpm (not quite as fast as the 1140 of the Unimatic, but still very impressive). The Imperial and Custom Imperial washers had this 1010 “Rapidry spin” as well as a 650 mid level spin and a 330 low speed spin. Agitation speeds remained at 330 normal or 220 delicate speeds. In '65 they also introduced the "Deep Action Agitator" which was also referred to as "Jet-Action". They had been experimenting with this 3-cone agitator since 1962 when they stated placing it in their coin-op machines, but for some reason waited until '65 to introduce it into the domestic line.
The 1970 line brought some very big changes. They introduced the new 1-18 washer with big 18lb perforated tub and the Jet-Cone agitator. The normal agitation speed was brought up from 330ppm to 360ppm and the spin speed was lowered from 1010 to about 660. They day's of the high speed spin were now over, even though its 660 was still the fastest spin available through the 1970's.
Of course in 1980 GM sold off Frigidaire it will never be the same

. For a few years they kept the same general look of the cabinet and control panel of the 1-18 but inside was a 1970's design Westinghouse Top-Loading washer, one of the worst top-loader washer designs ever. It was a very dark-day in applianceville. The first time I saw this new Frigidaire after catching my breath, I nearly cried. I don’t need to describe to anyone out there in applianceville what WCI is producing now as a top-loader.
If anyone has any additions to add this piece of history, that would be really great!