Pontiacs for the 1965 were now available with GM's new-for-1964 three-speed Turbo Hydramatic 400 transmission, often abbreviated as THM-400. This new unit replaced the older three-speed, four-range Roto-Hydramtic in the Catalina, as well as the four-speed Super-Hydramatic that was equipped in other Pontiacs. The THM-400 is torque converter based, similar in design to the Chrysler Torqueflite and Ford Cruise-O-Matic transmissions. Despite the Turbo Hydramatic 400 still bearing the "Hydramatic" name, it shared no design components with either of the older fluid-coupling based Roto or Super-Hydramatics. This new transmission was a large, but welcome, departure from the older transmissions, which were not as durable, smooth or fast as the new unit. The THM-400 also changed the shift pattern from the "P-N-D-S-L-R" to the safer and ultimately more modern "P-R-N-D-S-L." Although this transmission was new for 1964, it did lack some of the functionality of the older transmissions, like the low first gear ratios (3.50:1 or 3.97:1 for the Roto and Super Hydramatics respectively) or the split torque design where only 40% of the power went through the inefficient fluid couplings, which helped improve economy.