It can be said that Pontiac Division was probably made to use Roto so as to make Roto worth its money because Oldsmobile division didn't make enough units to justify its existence. Pontiac only used Roto from 1961-1964 in Catalina, Ventura, and Grand Prix. Bonneville and StarChief continued to use the 4 speed dual coupling called Super HydraMatic until the end of the 1964 model run.
In the familiar Oldsmobile and Pontiac shift quadrant, P-R-N-D-S-L or P-N-D-S-L-R, the "S" quadrant was for "Super" and not second. This shift arrangement with the "S" only applies to floor shift Pontiacs and all Pontiacs in 1964. In previous Pontiacs including 1963 Models with column shift the shift quadrant read 'DR' which refers back to the old Dual Range nomenclature which means drive left is fourth range and drive right is 3rd range. In the earlier four-speed Hydra-Matic, the "S" or "Super" quadrant (only used by Oldsmobile and floor shift Pontiacs and all 1964 Pontiacs) was actually third gear, allowing 1-2-3 shifts. This nomenclature was also used by Mercedes-Benz with the introduction of the four-speed type-3 automatic transmission. As with the Hydra-Matic, the "L" position was actually 1st and 2nd gears, holding the transmissions from shifting above 2nd gear. In Roto the L position meant 3.50 as first range, changing due to 2.93. Roto Engineers consider this two driving ranges. On Pontiacs with the exception 1964 model and all floor shift automatics, the shift indicator reads the same for Roto or the Super HydraMatic (dual coupling) and that is; 'DR' drive left and drive right or fourth range left and drive right 3rd range. Remember Roto HydraMatic is considered by HydraMatic Division as a three speed four range automatic and that is why the shift quadrant is the same between the 4 speed Super HydraMatic and the Four range Roto HydraMatic.
The shifting sequence was very different and much rougher than the Hydra-Matics that preceded it, or the Super Turbines and Turbo Hydramatics that followed it. The shift from 1st to 2nd or 2nd to 3rd range was long and drawn-out, ending with a harsh shift. The reason for this was that three things were happening. Not only was the transmission shifting to a very much higher range ( 2.93 to 1.56, but it was also simultaneously emptying the fluid coupling and making a mechanical lock-up. The wide gap in the reduction ratio between first and second gears combined with the direct mechanical connection to the engine to create a shift that could be firm enough to lug the engine. Because of the mechanical lock-up, there was sometimes a shudder felt as the transmission shifted into third gear (fourth range) by refilling the fluid coupling. Direct drive (1:1 ratio) is achieved by splitting engine power between the fluid coupling (used for first gear) and the front clutch (used for second gear), which are both applied to provide third gear, effectively locking the planetary gearsets and forcing them to spin at engine speed. The design is unique in that it provides third gear by applying first and second gears at the same time.
The smaller model 5 Roto Hydramatic uses the same principles of operation as the model 10. It is 9 lb (4.1 kg) lighter and much shorter in length — a necessary design parameter considering its placement in compact cars. The model 5 is not related to the "Dual Path Dynaflow" transmission used in the Buick Special and Skylark Models of 1961-1963. Buick's Dual Path was an air-cooled 2-speed unit with a planetary gearset inside the flywheel-mounted torque converter. The first Pontiac Tempests used a modified version of the Powerglide transaxle shared with the Chevrolet Corvair. But unlike the Corvairs, the TempesTorque was connected via a flexible drive shaft to an unconventional slant-4 (half of a 389 V-8) or an aluminum 215 c.i. V-8, which would be later sold to the Rover Group and be renamed the 3500 V-8. The smaller 61-05 as fitted to the Vauxhall Cresta was dubbed the "smoothamatic from Luton" in Cars Illustrated in Feb 1961 being quite taken with the overall refinement with the test car, also noting that full throttle starts could be made on slushy roads, perhaps giving away the rather tall 1st gear and minimal torque conversion. They also stated that the gearshifts were so smooth as to be practically imperceptible. The magazine The Motor, Dec 1960, also praised the high standard of smoothness with very lively performance. The performance was claimed to be almost as fast as with synchromesh gears and the 2-3 shift could be so gradual in gentle driving that the driver did not always realise it has happened. Certainly, the examples the author drove were equal to this and it seemed disappointing when the 61-05 model was discontinued in favour of the Powerglide in 1965.
