Morris Isis

Automatic transmission fluid capacity & service interval

Morris Isis automatic transmission fluid capacity ranges from 5,7 to 8,52 liters. Service intervals include checking at 5000 km and changing at 40000 km. The data covers 2 configurations.

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

TypeSpecifications
Isis Saloon, Series II (1956-1958)
  • Use: Normal
  • Capacity 8,52 liter (Dry fill)
  • Capacity 5,7 liter (Service fill)
  • Check 5000 km
  • Change 40000 km
  • Code: Borg Warner 35 3/1
Isis Traveller, Series II (1956-1958)
  • Use: Normal
  • Capacity 8,52 liter (Dry fill)
  • Capacity 5,7 liter (Service fill)
  • Check 5000 km
  • Change 40000 km
  • Code: Borg Warner 35 3/1

Additional Notes

  • The Morris Isis Series II carries a dry fill capacity of 8.52 liters for the automatic transmission, a figure that reflects the total fluid volume required when filling a completely drained or rebuilt unit, including fluid held within the torque converter and valve body passages.
  • The service fill capacity of 5.7 liters is notably lower than the dry fill, representing only the fluid displaced during a routine drain where the torque converter retains a significant portion of the previous charge.
  • The difference between the 8.52-liter dry fill and the 5.7-liter service fill amounts to approximately 2.82 liters, which is the volume that typically remains trapped in the torque converter during a standard service procedure.
  • Both the Isis Saloon and Isis Traveller in Series II trim share identical automatic transmission fluid capacities and service intervals, indicating a common drivetrain specification across both body configurations for the 1956-1958 production period.
  • Under normal use conditions, the automatic transmission fluid check interval is set at every 5,000 km, a relatively short monitoring cycle consistent with maintenance practices of mid-1950s automatic transmission technology.
  • The fluid change interval under normal use is specified at 40,000 km, which represents the full drain-and-refill service at which the 5.7-liter service fill capacity would apply.

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