BMC Austin Morris J4

Automatic transmission fluid capacity & service interval

BMC Austin Morris J4 uses automatic transmission fluid with a capacity of 6,4 liters. Service intervals include checks at 5000 km/3 months and 10000 km/3 months. The data covers 6 configurations.

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

TypeSpecifications
J4 (1.5) (1972-1974)
  • Use: Normal
  • Capacity 6,4 liter
  • Check 10000 km/ 3 months
  • Code: 3/1
J4 (1.6) (1972-1974)
  • Use: Normal
  • Capacity 6,4 liter
  • Check 10000 km/ 3 months
  • Code: 3/1
J4 Diesel (1972-1974)
  • Use: Normal
  • Capacity 6,4 liter
  • Check 10000 km/ 3 months
  • Code: 3/1
J4 (1.5) (1965-1972)
  • Use: Normal
  • Capacity 6,4 liter
  • Check 5000 km/ 3 months
  • Code: 3/1
J4 (1.6) (1965-1972)
  • Use: Normal
  • Capacity 6,4 liter
  • Check 5000 km/ 3 months
  • Code: 3/1
J4 Diesel (1965-1972)
  • Use: Normal
  • Capacity 6,4 liter
  • Check 5000 km/ 3 months
  • Code: 3/1

Additional Notes

  • The BMC Austin Morris J4 automatic transmission holds 6.4 liters across all listed configurations, covering the 1.5-liter, 1.6-liter, and Diesel variants from 1965-1974. A capacity at this level is consistent with a full transmission service fill, accounting for the fluid held within the torque converter, valve body, and transmission pan combined.
  • All six configurations share the identical 6.4-liter capacity figure, meaning the engine displacement difference between the 1.5 and 1.6 variants, as well as the fuel type difference in the Diesel variant, has no bearing on the automatic transmission fluid volume required.
  • Vehicles from 1965-1972, regardless of engine type, carry a check interval of every 5,000 km or 3 months, whichever comes first. The dual-trigger format, combining a distance threshold with a time threshold, ensures fluid condition is assessed even when annual mileage is low.
  • From 1972-1974, the check interval doubles to 10,000 km while the 3-month time component remains unchanged. The extended distance interval reflects a relaxed mileage-based schedule, though the time-based trigger continues to apply at the same frequency as the earlier production period.
  • The 1972 model year marks the boundary between the two check interval specifications. Units produced in 1972 fall under the 1965-1972 group with the 5,000 km interval, while those from the same year onward into the 1972-1974 group follow the 10,000 km schedule, making the production date within 1972 a relevant factor in determining the applicable interval.
  • All specifications are listed under normal use conditions. In automotive service terminology, normal use typically refers to standard operating patterns without the added mechanical stress associated with severe-duty classifications such as frequent towing, extended idling, or extreme temperature exposure.

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