Reconditioned BMW 1 Series Gearbox

Why can two BMW 1 Series 2.0d models take different gearboxes?

Engine capacity alone does not identify a specific gearbox on the 1 Series. The 2.0d is a perfect example of this pitfall: depending on the year and engine code, the unit is a M47D20 (E81/E87 generations, up to around 2007) or a N47D20 (from 2007 onwards, E81/E87 then F20/F21 generations) — two mechanically distinct families that do not share the same bell housings or gearbox references. The same logic applies to the 3.0i between the N52B30 and earlier variants: the expected GS6 reference varies. Before placing any order, the engine code — not simply the engine capacity — is therefore the essential starting point.

Eight engine codes across six engine variants: how to find your way

The collection covers the 1 Series from 2004 to 2019, spanning three generations (E81/E87, F20/F21, F52). It includes eight distinct engine codes — N47D16A, N46B20, N43B20, N52B30, B37D15A, B37C15A, M47D20, N47D20 — spread across six engine capacities (1.5d, 1.6d, 2.0d, 2.0i, 3.0, 3.0i), all fitted with a 6-speed manual gearbox. The 1.5d engines in the facelifted F20 carry the codes B37D15A or B37C15A — two closely related but distinct variants: checking which one appears on your unit will prevent a return. Gearbox references in this range all begin with GS6 (e.g. GS6-17BG, GS6-45BZ, GS6-45DZ), but the suffixes encode the maximum torque rating and the engine interface — two parameters that differ from one engine code to another.

Two reconditioning options available

Gearboxes in this collection are offered under two options: exchange, where you return your old unit, and rebuilding your own gearbox, where your own unit is reconditioned and returned to you — a useful option when the exact reference is hard to find or when the gearbox has a specific configuration (such as the short-ratio version of the 3.0i 265 hp). The choice between the two depends on availability and the condition of your original unit.