Power for the turbo diesel E 350 Bluetec will also rise to 192kW (up from 185kW), while torque remains static at a sizable 620Nm.
Meanwhile, average fuel consumption will drop from the current model's 7.4 l/100km to a thrifty 5.3 l/100km for the E 350 sedan, no doubt thanks to the 9G-Tronic's greater ratio spread.
Unlike the upcoming CLS facelift, which pairs a nine-speeder with every engine bar the CLS 63 AMG's 5.5 litre biturbo V8, the 9G-Tronic won't be available on any E-Class bar the E 350 variant - at least not initially.
The E 200, E 250, E 300 hybrid, E 400, E 220 CDI and E 250 CDI will continue to use Benz's familiar 7G-Tronic seven-speed auto, though the E 220 CDI will get a slight bump in power to 130kW (an increase of 5kW).
Meanwhile, the E 400 range will receive a new 3.5 litre engine, which displaces half a litre more than the current 3.0 litre twin-turbo V6. Power and torque will be unchanged at 245kW and 480Nm respectively, but the larger engine will emit 17g/km less carbon.
Mercedes-Benz's Collision Prevention Assist Plus will also be standard across the 2015 E-Class range, capable of automatically braking to prevent a collision with a stationary car at speeds up to 48km/h, and prevent rear-end collisions at speeds up to 38km/h.
Local specs have yet to be announced, but as the E 350 Bluetec V6 diesel is currently not sold in Australia it's probably fair to assume that the 9G-Tronic won't be in Australia-bound E-Classes for a while.
Instead, we'll have our first taste of the transmission in the CLS 500, which is due to launch locally in the first quarter of next year.