Sisu Polar

Differential fluid capacity & service interval

Sisu Polar differential fluid specifications cover normal use with a capacity range of 18 to 26 liters. The data includes 6 configurations.

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

TypeSpecifications
  • Polar V6 (2010- )
  • Rear, leading
  • Use: Normal
  • Capacity 26 liter
  • Code: FRMP-13-S
  • Polar V6 (2010- )
  • Rear, trailing
  • Use: Normal
  • Capacity 18 liter
  • Code: FRDP-13-S
  • Polar V8 (405 kW) (2010- )
  • Rear, leading
  • Use: Normal
  • Capacity 26 liter
  • Code: FRMP-13-S
  • Polar V8 (405 kW) (2010- )
  • Rear, trailing
  • Use: Normal
  • Capacity 18 liter
  • Code: FRDP-13-S
  • Polar V8 (440 kW) (2010- )
  • Rear, leading
  • Use: Normal
  • Capacity 26 liter
  • Code: FRMP-13-S
  • Polar V8 (440 kW) (2010- )
  • Rear, trailing
  • Use: Normal
  • Capacity 18 liter
  • Code: FRDP-13-S

Additional Notes

  • The Sisu Polar carries two distinct rear differential fluid capacities depending on axle position: the leading rear differential holds 26 liters, while the trailing rear differential holds 18 liters.
  • A 26-liter capacity for the leading rear differential is a substantial fill volume, consistent with heavy-duty tandem axle assemblies found in commercial trucks where the leading unit bears primary load transfer responsibilities.
  • The 8-liter difference between the leading and trailing rear differentials across all configurations suggests a structural distinction between the two axle units rather than a variation in fluid specification.
  • All three powertrain variants — the V6, the V8 at 405 kW, and the V8 at 440 kW — share identical rear differential capacities of 26 liters (leading) and 18 liters (trailing), indicating the differential assemblies are common across engine outputs.
  • All capacity figures listed apply under normal use conditions, meaning the intervals and fill volumes are not adjusted for severe-duty operation in the specifications provided.
  • The two V8 variants differ only in output rating — 405 kW versus 440 kW — yet both share the same differential fluid capacities, pointing to a shared drivetrain architecture between the two power levels.

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