Second Hand BMW i3 Gearbox

The BMW i3 was produced from 2013 onwards, with a facelift in 2017 that brought some specification updates, so it's worth naming which side of that 2017 boundary your donor car falls on. Because the i3 uses a single-speed reduction gearbox integrated with its electric drive unit, the key fitment detail is the motor and drive unit specification tied to your battery generation (60Ah, 94Ah, or 120Ah), not a traditional gearbox type. Whether a unit from a pre-2017 car crosses correctly to a post-2017 car is something you should confirm with the breaker against your registration, as drive unit specs can vary across that boundary. Never assume fitment without that check.

Yes, this is one of the most important fitment questions for the i3: the Range Extender model carries a small two-cylinder petrol engine alongside the electric motor, which affects the rear subframe and drive unit packaging compared to the full BEV. The reduction gearbox is integrated into the rear drive unit, and the two variants use different rear-end assemblies, so a BEV unit is unlikely to be a straightforward swap into a REx car and vice versa. Always tell the breaker whether your car is the REx or BEV version and confirm compatibility against your registration before purchasing.

Trim level alone does not determine gearbox fitment on the i3, but the i3s is a meaningfully different specification: it uses a higher-output motor producing around 184hp compared to the standard i3's 170hp, and the rear drive unit and reduction gearbox are specific to that higher-output motor. So while 'trim' in the cosmetic sense doesn't matter, if your car is badged i3s you need a drive unit sourced from another i3s, not a standard i3. Confirm the exact motor specification with the breaker against your registration to make sure the donor car matches yours.

Year does matter on the i3 because BMW updated the battery and motor specifications across the car's production life — moving from 60Ah to 94Ah to 120Ah battery packs — and the integrated drive unit can differ accordingly. The 2017 facelift is a useful reference point, but battery generation changes don't align perfectly with that styling update, so year alone isn't a reliable guide. The most useful thing you can do is supply your registration to the breaker so they can match the exact drive unit specification rather than relying on model year alone.

Because the i3's reduction gearbox is part of an integrated rear drive unit that works in conjunction with the motor and inverter, mixing components across different battery generations (60Ah, 94Ah, 120Ah) introduces real compatibility uncertainty. Whether the mechanical interface is identical across those generations is something you should confirm with the breaker against both registrations, as ancillary and mounting changes mid-production are common on EVs and cannot be stated as fact here. A reputable breaker who specialises in EVs or BMW i-models will be best placed to advise on whether the units are interchangeable.

The i3's drive unit does involve electronic integration between the motor, inverter, and vehicle systems, and whether the reduction gearbox or wider drive unit assembly requires coding or pairing to your specific car is something you should confirm with the breaker and ideally a BMW specialist before buying. This falls into the category of ECU pairing and immobiliser coding that cannot be stated as straightforward fact for this part. It is worth asking the breaker whether they can supply any coding history for the donor unit, and factor in potential coding costs when budgeting for the job.