The gearbox of the BMW i8 occupies a unique place, as this plug-in hybrid 2+2 coupé launched in 2014 combines two powertrains and therefore two separate transmissions. However futuristic and reliable this architecture may be, it is not immune to wear: over time, even the most sophisticated systems begin to show signs of weakness. How do you recognise a problem, how does the repair process work, and when should you consider a replacement? EDEN BOITES answers all of these questions in this comprehensive guide.
The Engine and Gearbox of the BMW i8
The BMW i8 houses its combustion engine in a mid-rear position — a notable technical feature. It is a 1.5-litre three-cylinder unit, light and compact, producing 231 hp with a maximum torque of 320 Nm; power is delivered to the rear wheels via a six-speed automatic gearbox. This is complemented by an auxiliary 131 hp electric motor producing 250 Nm, which drives the front wheels from the moment of departure via a two-speed automatic gearbox. The combined output of both motors reaches 362 hp, enabling a 0–100 km/h sprint in 4.2 seconds. This dual transmission setup makes the i8 a vehicle whose maintenance demands genuine expertise.
How to Tell if the BMW i8 Gearbox Is Malfunctioning
When something goes wrong, your BMW i8's transmission sends signals that need to be correctly interpreted. The illumination of the engine warning light — the Check Engine light — indicates an issue with engine components or the vehicle's general operation. This is often accompanied by symptoms specific to automatic transmission failure, which frequently appear together:
- unusual noises resembling grinding, caused by metal-on-metal friction between gear components;
- the gear selector jumping automatically, which can place significant strain on the engine;
- hesitation during gear changes, with the gears struggling to engage;
- a burning smell, usually linked to contamination of the gearbox oil, sometimes accompanied by leaks and dark fluid stains.
BMW i8 Gearbox Repair
An automatic transmission is a complex system — even more so on a hybrid with two motors. At the first sign of a fault, entrust the repair to a professional, who will work through two essential stages.
1. Diagnosing the Fault
To pinpoint the exact source of the problem, the specialist uses a diagnostic scanner to detect error codes and sensor failures. Pressure tests are also carried out to verify that the transmission is functioning correctly. In some cases, the automatic gearbox must be dismantled to identify the root cause of the fault.
2. The Repair Itself
Depending on the diagnosis, the mechanic may replace certain faulty gearbox components (clutch packs, seals, solenoids, etc.). A transmission fluid change is sometimes necessary, using oil suited to an automatic gearbox and of a viscosity that meets the manufacturer's specifications. Finally, the transmission pressure is adjusted and the regulating valves are set correctly.
When Should You Replace the BMW i8 Gearbox?
This decision depends on several factors and requires a thorough inspection of the transmission. Only a specialist with the appropriate tools can make that call. If your mechanic recommends a replacement, the exchange option allows you to fit a reconditioned gearbox rather than a brand-new one: simply choose the correct reference from our gearbox catalogue or our BMW range, then hand it over to the professional of your choice. For further reading on electrified models, take a look at our guides on the BMW i4 gearbox and the BMW i3 gearbox. If you are experiencing stiff gear changes, also see our guide on why your gearbox feels stiff.
Frequently Asked Questions
Does the BMW i8 Really Have Two Gearboxes?
Yes. The rear combustion engine uses a six-speed automatic gearbox, while the front electric motor relies on a two-speed automatic gearbox. It is this architecture that makes its maintenance so specific.
What Does a Burning Smell on the i8 Mean?
It often indicates contamination of the gearbox oil, sometimes accompanied by leaks. A prompt diagnosis prevents the problem from damaging the transmission's internal components.
Does the Check Engine Light Relate to the Gearbox?
It signals an issue with the engine or the vehicle's general operation, which may include the transmission. Only reading the fault codes can identify the precise source of the problem.
Can a Reconditioned Gearbox Be Fitted to an i8?
Yes, provided the reference matches your vehicle. A reconditioned exchange gearbox is fitted by a professional just like an original unit.
Why Choose EDEN BOITES?
EDEN BOITES specialises in reconditioned BMW gearboxes sold on an exchange basis. Every unit undergoes a full reconditioning process and a rigorous quality check before dispatch. You benefit from:
- a warranty of up to 24 months;
- payment in instalments, in up to 10 instalments;
- delivery throughout France and the European Union, with lead times confirmed on quote;
- a satisfaction-or-money-back guarantee on the exchange, subject to our Terms and Conditions;
- collection of your old unit at the time of delivery of the new one.
Restore your hybrid coupé to its full performance: browse our BMW gearbox range and request your personalised quote.
