BMW 3 series, E21 (USA)

Differential fluid capacity & service interval

BMW 3 series, E21 (USA) differential fluid capacity ranges from 0,9 to 0,95 liters. Service intervals include checking at 15000 or 125000 miles and changing at 25000 or 30000 miles. The data covers 3 configurations.

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

TypeSpecifications
  • 320 i (1979-1982)
  • Rear
  • Use: Normal
  • Capacity 0,95 liter (Initial fill)
  • Capacity 0,9 liter (Service fill)
  • Check 15000 miles/ 12 months
  • Change 30000 miles/ 24 months
  • 320 i (1976-1979)
  • Rear
  • Use: Normal
  • Capacity 0,95 liter (Initial fill)
  • Capacity 0,9 liter (Service fill)
  • Check 125000 miles/ 12 months
  • Change 25000 miles/ 24 months
  • 320 i (1976-1979)
  • Rear
  • Use: Normal
  • Capacity 0,95 liter (Initial fill)
  • Capacity 0,9 liter (Service fill)
  • Check 125000 miles/ 12 months
  • Change 25000 miles/ 24 months

Additional Notes

  • The BMW 3 Series E21 (USA) rear differential carries an initial fill capacity of 0.95 liter, which represents the volume required when the unit is dry, such as after a rebuild or component replacement.
  • The service fill capacity is rated at 0.9 liter across both the 1976-1979 and 1979-1982 320i configurations, reflecting the slightly lower volume needed when some residual fluid remains in the housing during a routine drain and refill.
  • The 1976-1979 320i specifies a differential fluid check interval of 125,000 miles or 12 months under normal use conditions, paired with a change interval of 25,000 miles or 24 months.
  • The 1979-1982 320i carries a notably shorter check interval of 15,000 miles or 12 months under normal use conditions, compared to the 125,000-mile check interval assigned to the earlier 1976-1979 variant.
  • The change interval for the 1979-1982 320i is set at 30,000 miles or 24 months under normal use conditions, which is 5,000 miles longer than the 25,000-mile change interval specified for the 1976-1979 320i.

Other Systems