Ursus Bison

Differential fluid capacity & service interval

Ursus Bison differential fluid capacity is 3,5 liters. Service intervals include checks at 100 hours and changes at 800 hours or 12 months. The data covers 5 configurations.

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

TypeSpecifications
  • Bison 105-65 (2WD+4WD) (1984- )
  • Front
  • Use: Normal
  • Capacity 3,5 liter
  • Check 100 hours
  • Change 800 hours/ 12 months
  • Bison 120-85 (2WD+4WD) (1984- )
  • Front
  • Use: Normal
  • Capacity 3,5 liter
  • Check 100 hours
  • Change 800 hours/ 12 months
  • Bison 145-100 (2WD+4WD) (1984- )
  • Front
  • Use: Normal
  • Capacity 3,5 liter
  • Check 100 hours
  • Change 800 hours/ 12 months
  • Bison 160-110 (2WD+4WD) (1984- )
  • Front
  • Use: Normal
  • Capacity 3,5 liter
  • Check 100 hours
  • Change 800 hours/ 12 months
  • Bison 85-50 (2WD+4WD) (1984- )
  • Front
  • Use: Normal
  • Capacity 3,5 liter
  • Check 100 hours
  • Change 800 hours/ 12 months

Additional Notes

  • The Ursus Bison front differential holds 3.5 liters across all five variants covered — the 85-50, 105-65, 120-85, 145-100, and 160-110 — regardless of whether the tractor is configured as 2WD or 4WD.
  • A 3.5-liter front differential capacity is a moderate fill volume, consistent with a compact axle housing rather than a heavy-duty portal or planetary front axle assembly.
  • Under normal use conditions, the front differential fluid change interval is set at 800 hours or 12 months, whichever comes first, applying uniformly to all five Bison variants listed.
  • The 12-month calendar limit on the change interval means that even in low-hours operation, the fluid is due for replacement once a year under normal use conditions.
  • A separate check interval of 100 hours is specified under normal use conditions, meaning the fluid level is to be inspected well before a full drain-and-fill is due.
  • The 100-hour check interval relative to the 800-hour change interval represents an 8-to-1 ratio, indicating that multiple inspections are expected between each full fluid change cycle.
  • The front differential specifications are identical across the 2WD and 4WD configurations within each Bison variant, meaning drivetrain layout does not alter the stated capacity or service intervals for the front differential.
  • All five Bison variants share the same 3.5-liter capacity and identical service intervals, indicating a common front differential design across the model range starting from 1984.

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