I am 76 years old and have never spent a day of my life that didn't include a Dynaflow transmission......
They hauled me home in grandma's new Packard, but grandpa had a '49 Roadmaster with a Dynaflow. My first car had a Dynaflow, I've had numerous cars with them in the interim, and I currently still have my "63 Electra with its "Turbine Drive" Dynaflow transmission. Dynaflow was the first CVT made anywhere. Current CVT's are not reliable because nobody knows or works with the Dynaflow principle. All they need to do is to make a front-wheel-drive version of Dynaflow and they'd be set.
That video gave a good explanation of how Dynaflow worked. Folks that knock Dynaflow either don't understand it or try to make it something it is not. A big Buick was not a drag car. IT was designed to get you from point A to point B in total silence and absolute comfort. A 401 and Dynaflow was designed to propel a 4800 pound car from rest in a reasonable amount of time, in silence, with absolute competence. It mattered not if it got bested from the stoplight. IF you wanted a big car that was fast, you bought a Chrysler with a 413 and a 727 Torqueflite. THAT was a fast big car. As to gas mileage, my Buick got mileage in keeping with its contemporaries and actually got better mileage than some, namely a Ford 390. Wildcats and Centurys were called banker's hotrods, but that was due to their more sporting livery, rather than any improvement in performance. Wildcats and Centurys had the same drivetrain as comtemporary Electras and Roadmasters. Remember also, when Dynaflow came out in 1948, it was coupled to a long-stroke, slow, low-revving Straight 8 engine. The combination of the torque converter principle and the slow-revving engine, it did make performance rather leisurely. Even when the V-8 came out in 1953, it was not known as a spunky revver. Not really until 1955 did the 322 get exciting acceleration. 1956 got a hotter cam and larger valves, but that is a story for another day.
The video omitted details I thought would be important. The introduction of variable pitch, the aluminum bell housing introduced late in '56 on Century only. Moving the starter ring gear from the flywheel to the torque converter, again in late '56 on Century and on all production for '57. This solved a chronic problem of breaking off the nose of the starter when the transmission and engine expanded at different rates. Pre-'56 cars had full flywheels, later cars had triangle flex plates. The 1953 Cadillac tooling that was hastily retrieved to convert the '61 Buicks to open driveshaft after the bean counters ix-nayed the introduction of the Super Turbine (TH 400) transmission for the 1961 model year. Contrary to the video, the TH 400 was not a corporate transmission, it was a Buick transmission. Corporate stole it because Cadillac griped enough. The basic Dynaflow transmission was unchanged mechanically from 1948 to 1963. The torque converter was changed almost every year. You could take a '56 Century with a '63 torque converter and smoke more potent vehicles.
It is generally accepted by Buick fans that Ned Nickles was the driving force behind Dynaflow. And that Dynaflow was an adaptation of a contraption used to power gun turrets in WW2. Buick built gun turrets during the war, exposing engineers to the gun turret drive system. That man Kelly mentioned in the video is someone I'm not familiar with.
Chevy messed up when they introduced Power Glide that they didn't use the 261 truck engine to give a bit more power. And that they made Power Glide shift in 1953 instead of just giving it the new V-8 engine. Dad had a '50 Bel-Air hardtop he dearly loved that had a 261 in it. It was a good runner as I remember. Not a Buick or anything like that, but it was very competent for a six-cylinder Chevy.
Buick guys have a saying, "When Dynaflow stops leaking, you need to check the fluid". They leak. Always have, always will. When they came out in '48, the fluid used was whale oil. IT was the only hydraulic fluid available at the time that could withstand the extra heat generated in the torque converter. Later, Type A fluid came out, and I think it was based on soybean oil originally. Petroleum-based fluid makes the seals leak. Not enough that you have to add frequently, but enough to make a mess. The new Mercon-whatever makes Dynaflow leak like a sieve, but also increases performance.
And as an aside, you may have noticed the Desert Sand '63 Electra four-door hardtop with the black vinyl top in the video. I think I know that car. Last I knew, it was in New Jersey. it has bucket seat interior with floor shift like my Electra. If it is the one I think it is, I almost bought that car. Very nice, mostly original car. Every Buick from 1962 thru 1964 had the chrome strip that divided the vinyl top regardless of body style. That Electra is the only big Buick I ever saw with a vinyl top until about 1965 or so. White vinyl tops were fairly common on '62 Wildcats.