 The Mercedes-Benz first series of automatic transmission started off in 1961 with the K4A 025 (Kupplungs-4-Gang-Automatik bis 25 kpm Eingangsdrehmoment; clutch-4-gear-automatic with 181 ft·lb maximum input torque; without type designation) and was followed up by a family with a more reliable design.This started in 1964 with the K4B 050 (without type designation) and ended up in the K4C 025 and K4A 040 (type 722.2) as the four-speed automatic transmissions.Later, when the torque converter technique was fully established, the W3A 040 and W3B 050 (type 722.0) were launched as three-speed derivates for V8 engines.