BMW 3 series, E21 (USA)

Automatic transmission fluid capacity & service interval

BMW 3 series, E21 (USA) automatic transmission fluid capacity ranges from 2 to 5,7 liters. Service intervals include checking at 15000 to 125000 miles or 12 months, and changing at 25000 to 30000 miles or 24 months. 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)
  • Use: Normal
  • Capacity 5,7 liter (Initial fill)
  • Capacity 2 liter (Service fill)
  • Check 15000 miles/ 12 months
  • Change 30000 miles/ 24 months
  • Code: ZF 3HP22 3/1
320 i (1976-1979)
  • Use: Normal
  • Capacity 5,3-5,7 liter (Initial fill)
  • Capacity 2 liter (Service fill)
  • Check 125000 miles/ 12 months
  • Change 25000 miles/ 24 months
  • Code: ZF 3HP22 3/1
320 i (1976-1979)
  • Use: Normal
  • Capacity 5,3-5,7 liter (Initial fill)
  • Capacity 2 liter (Service fill)
  • Check 125000 miles/ 12 months
  • Change 25000 miles/ 24 months
  • Code: ZF 3HP22 3/1

Additional Notes

  • The BMW 3 Series E21 (USA) 320i produced from 1976-1979 carries an initial fill capacity of 5.3-5.7 liters, which reflects the total fluid volume required when filling a dry or overhauled automatic transmission from empty, including the torque converter and all internal passages.
  • The 1976-1979 320i service fill capacity is 2 liters, a figure significantly lower than the initial fill range, as a routine fluid change only replaces the portion drained from the pan without evacuating the torque converter.
  • The 1979-1982 320i carries a fixed initial fill capacity of 5.7 liters, sitting at the upper boundary of the 5.3-5.7 liter range specified for the earlier 1976-1979 variant, while the service fill capacity of 2 liters remains unchanged between both production periods.
  • The check interval for the 1976-1979 320i is listed at 125,000 miles or 12 months under normal use conditions, a notably high mileage threshold that reflects a monitoring interval rather than a fluid replacement schedule.
  • The 1979-1982 320i has a check interval of 15,000 miles or 12 months under normal use conditions, a substantially shorter mileage figure compared to the 125,000-mile check interval assigned to the 1976-1979 variant.
  • The fluid change interval for the 1976-1979 320i is set at 25,000 miles or 24 months under normal use conditions, while the 1979-1982 320i extends the change interval to 30,000 miles under the same 24-month time limit.

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