Reconditioned BMW Gearbox

BMW Gearboxes: 6-speed manual across almost the entire range, but not a single gearbox family

Across the BMW models covered here — Série 1, Série 3, Série 4, Série 5, X1, X3, X4 and Série 2 Gran Tourer, from 2003 to 2022 — the only transmission offered is the 6-speed manual gearbox. No dual-clutch, no torque-converter automatic within this scope. That choice clearly defines the catalogue: if your BMW is fitted with a Steptronic or a ZF 8HP, this page is not for you. If, on the other hand, you are looking for a reconditioned manual gearbox for a 4- or 6-cylinder diesel engine, or for a petrol unit from the same period, you are in the right place.

Diesel: two generations of 4-cylinder, one 6-cylinder with multiple variants

On the diesel side, the variety of engine codes is the first pitfall. For the 2.0d, six codes exist side by side: M47D20, N47D20, N47D20A, B47D20, B47C20A and B47C20B. These families correspond to distinct generations (M47, N47, then B47) that did not share the same gearboxes: the same Série 3 2.0d can therefore require very different GS6 references depending on its model year. The 1.6d (code N47D16A) and the 1.5d (B37C15A, B37D15A) round out the range on entry-level models such as the Série 1 and the X1. For the 3.0d, the codes 306D2, 306D3, 306D5, M57D30 and M57N2 denote several evolutions of the 6-cylinder M57: here again, the engine designation alone is not enough — the exact code stamped on the block remains the only reliable reference.

Petrol: from the M54 to the B58, units that share no gearbox

On the petrol side, the catalogue covers the 2.0 (N43B20, N46B20, N20B20, B48B20), the 2.0i with the same code families, the 2.5 (M54B25, N52B25, N53B25), the 3.0 and the 3.0i. Some codes carry a body designation — N20B20 (E84) for the X1, B48B20 (F48) for the facelifted X1, N55B30 (435i) or B58B30 (440i) for the Série 4 — which means the associated gearbox also depends on the chassis, not just the engine. An N20B20 fitted to an E84 does not necessarily require the same GS6 reference as an N20B20 on an F30. For the 6-cylinder petrol units, the progression from the M54 through the N52, N53, N54, then N55 and B58 spans nearly twenty years: each generation requires its own gearbox. The catalogue references (in the format GS6-xxDZ or GS6-xxBZ) reflect these distinctions; two references that look similar may be incompatible.

Exchange or rebuild: two options depending on the condition of your unit

The BMW gearboxes in this collection are available on an exchange basis or as a rebuild of your own unit. These two options do not suit the same situations: the first is the right choice when the gearbox is beyond use and a short lead time is the priority; the second applies when the customer's unit can be reconditioned and returned as original — particularly useful for rare references such as the 3.0d or 3.0i, where exchange stock is more limited. In both cases, providing the full engine code is the only way to avoid a reference error across a BMW parc as segmented as this one.