722.6

Introduced in 1996 behind the V8 of the W140 S-Class, the 722.6 replaced the hydraulically controlled 4G-TRONIC family with a cleaner idea: five gears, full electronic shift control with adaptive programs, and a torque-converter lock-up clutch that could slip progressively to cut heat and consumption. Mercedes-Benz called the family W5A — Wandler-5-Gang-Automatik — with classifications from W5A300 to W5A900 naming each version’s maximum input torque. Internally it was NAG1, the first New Automatic Gearbox generation, and despite the extra ratio it used fewer main components than the four-speed it replaced.

That torque spread put the 722.6 behind almost everything Stuttgart built for a decade — C-Class diesels, E-Class wagons, every R129 and R230 SL, and at 900 N·m the Maybach 62 and SLR McLaren. After the DaimlerChrysler merger it crossed the Atlantic as the NAG1 in the Chrysler 300C, Dodge Charger and Jeep Wrangler. Even the 7G-TRONIC’s arrival in 2003 couldn’t retire it: the 722.6 soldiered on behind the V12s the new gearbox couldn’t handle, staying in production until 2020.