BMW 8 series Convertible, G14 / F91 (USA)

Automatic transmission fluid capacity & service interval

BMW 8 series Convertible, G14 / F91 (USA) uses automatic transmission fluid with a capacity range of 9,28 to 9,35 liters. The data covers 6 configurations.

The configuration chart below lists fill volumes and service intervals for each engine and trim variant.

TypeSpecifications
M8 Competition xDrive Convertible (2020- )
  • Use: Normal
  • Capacity 9,35 liter
  • Code: ZF GA8HP76X 8/1
840i Convertible (2019- )
  • Use: Normal
  • Capacity 9,28 liter
  • Code: ZF GA8HP51Z 8/1
840i xDrive Convertible (2019- )
  • Use: Normal
  • Capacity 9,28 liter
  • Code: ZF GA8HP51X 8/1
M8 xDrive Convertible (2019- )
  • Use: Normal
  • Capacity 9,35 liter
  • Code: ZF GA8HP76X 8/1
M850i xDrive Convertible (2019- )
  • Use: Normal
  • Capacity 9,35 liter
  • Code: ZF GA8HP76X 8/1
M850i xDrive Convertible (2018-2019)
  • Use: Normal
  • Capacity 9,35 liter
  • Code: ZF GA8HP76X 8/1

Additional Notes

  • The BMW 8 Series Convertible (G14/F91) automatic transmission fluid capacities fall into two distinct values across the lineup: 9.28 liters for the 840i variants and 9.35 liters for the M8, M8 Competition, and M850i xDrive variants.
  • The 9.28-liter capacity shared by the 840i Convertible and 840i xDrive Convertible reflects a service fill volume typical of a sealed automatic transmission, representing the total fluid required to bring the unit to its correct operating level during a fluid service.
  • The 9.35-liter capacity found in the M8 xDrive, M8 Competition xDrive, and M850i xDrive Convertible is marginally higher than the 840i figure, consistent with the larger transmission units typically paired with higher-output engines in performance-oriented configurations.
  • All six configurations carry a normal use condition designation, meaning the listed capacities and service intervals apply to standard operating conditions rather than severe or extended-duty cycles.
  • The M850i xDrive Convertible appears across two separate year-range entries, with the 2018-2019 entry and a second entry starting from 2019, both specifying an identical 9.35-liter automatic transmission fluid capacity under normal use conditions.
  • The M8 Competition xDrive Convertible shares the same 9.35-liter automatic transmission fluid capacity as the non-Competition M8 xDrive Convertible, indicating no transmission fluid volume difference between those two performance variants despite their differing power outputs.

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