BMW 6 series, E24 (USA)

Differential fluid capacity & service interval

BMW 6 series, E24 (USA) differential fluid capacity ranges from 1,5 to 1,9 liters. Service intervals include normal use and flexible use via an on board maintenance system. The data covers 7 configurations.

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

TypeSpecifications
  • 635 CSi (1987-1989)
  • Rear
  • Use: Flexible (on board maintenance system)
  • Capacity 1,9 liter
  • 635 CSi (1987-1989)
  • Rear, with differential lock
  • Use: Flexible (on board maintenance system)
  • Capacity 1,9 liter
  • M6 (1987-1989)
  • Rear
  • Use: Flexible (on board maintenance system)
  • Capacity 1,9 liter
  • Code: 210
  • 633 CSi (1979-1984)
  • Rear
  • Use: Normal
  • Capacity 1,5-1,6 liter
  • 633 CSi (1979-1984)
  • Rear, with differential lock
  • Use: Normal
  • Capacity 1,5-1,6 liter
  • 630 CSi (1976-1979)
  • Rear
  • Use: Normal
  • Capacity 1,5-1,6 liter
  • 630 CSi (1976-1979)
  • Rear, with differential lock
  • Use: Normal
  • Capacity 1,5-1,6 liter

Additional Notes

  • The BMW 6 Series E24 (USA) rear differential fluid capacity splits into two distinct values across the model range: 1.5-1.6 liters for the 630 CSi and 633 CSi, and 1.9 liters for the 635 CSi and M6.
  • The 1.5-1.6 liter range listed for the 630 CSi and 633 CSi reflects a tolerance band rather than a single fixed fill point, which is common in rear differential servicing where the correct level is confirmed by fluid reaching the fill plug opening.
  • The 635 CSi (1987-1989) and M6 (1987-1989) share the same 1.9 liter rear differential capacity, representing a larger unit compared to the earlier 630 CSi and 633 CSi differentials.
  • The 630 CSi (1976-1979) carries identical capacity specifications of 1.5-1.6 liters for both the standard rear differential and the rear differential equipped with a differential lock, indicating the locking mechanism does not alter the fluid volume requirement.
  • The same capacity parity between standard and locking differential configurations also applies to the 633 CSi (1979-1984), where both variants share the 1.5-1.6 liter specification.
  • The 635 CSi (1987-1989) rear differential with a differential lock holds 1.9 liters, matching the standard differential on the same model, again showing no capacity difference introduced by the locking unit.
  • Service intervals for the 630 CSi and 633 CSi rear differentials are listed under normal use conditions, while the 635 CSi and M6 intervals are governed by a flexible schedule tied to the on-board maintenance system, reflecting a generational shift in service interval methodology within the E24 lineup.
  • The flexible interval designation on the 635 CSi and M6 means the on-board maintenance system calculates service timing based on operating conditions rather than a fixed mileage or time threshold, which is the basis for the 1.9 liter capacity entries in those rows.

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