The ease of shifting of the new 9G-TRONIC—a focal point during development—is due to a comprehensive package of measures. These include the novel direct control system which enables short, barely perceptible gear changes.
Three speed sensors monitor operation and provide the transmission control system with corresponding data for effective shifting. Here it is possible for several gears to be jumped when accelerating or decelerating, should the driving conditions call for it.
To ensure the reliable and efficient supply of the durable and shear-resistant 2nd-generation synthetic engine oil, the new automatic transmission is fitted with two pumps. The considerably smaller mechanical main pump, featuring an off-axis design, is located next to the main shaft and is chain-driven and fed by a separate electric auxiliary pump. This design enables the flow of lubrication and coolant to be controlled actively on demand and also means that the 9G-TRONIC can benefit from a start/stop system. Due to the first direct control system in a planetary automatic transmission with nine gears, it has also been possible to significantly increase hydraulic efficiency within the transmission.
