Reconditioned BMW 3 Series Gearbox

3 Series from 2005 to 2019: the same 6 speeds, but very different gearboxes depending on the engine

From the E90 in 2005 to the F30/F31 through to 2019, the 3 Series spanned two generations and a profound shift in its engine line-up. The 6-speed manual gearbox was the only type offered across this range, yet it was never a fixed unit: the GS6 gearbox families come in several variants (GS6-17, GS6-37, GS6-45, GS6-53, GS6X37, GS6X45), each paired with specific engines. The same bodyshell can therefore take mechanically incompatible gearboxes depending on which engine was fitted at the factory.

Diesel: three generations of 2.0d and 3.0d engines

The 2.0d accounts for the bulk of the catalogue with ten distinct references. It was fitted successively with the M47D20 (E90 phase 1), the N47D20 (E90 phase 2 and early F30), then the B47D20 (F30 from around 2015 onwards). These three engines do not share the same gearbox: mixing up references between an N47 and a B47 is a common identification mistake. The 3.0d is based on the M57D30 (306D2) and M57N2 (306D3) families — two variants of the diesel straight-six that must not be interchanged.

Petrol: from the M54 to the B48, a technological break between generations

On the petrol side, the timeline is equally critical. The M54B30 (older naturally aspirated generation) gives way to the N52B30, then the N53B30 and the N54B30 (twin-turbo) on the 3.0i models, each paired with a GS6 gearbox of a different ratio and interface. On the 2.0i and 2.0 models, the succession N43B20 → N20B20 → B48B20 follows the same logic: the engine code stamped on the block is the only reference that allows you to select the correct GS6 reference. The N46B20 rounds out the range on certain entry-level E90 versions. Checking this code before placing any order avoids a return and unnecessary delays.