International Harvester 55 / 56

Automatic transmission fluid capacity & service interval

International Harvester 55 / 56 uses automatic transmission fluid with a capacity of 34 liters. Service intervals include checking every 200 hours and changing every 800 to 1000 hours. The data covers 4 configurations.

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

TypeSpecifications
  • 1255 XL (1981-1985)
  • Hydraulic system
  • Use: Normal
  • Capacity 34 liter
  • Check 200 hours
  • Change 800 hours
  • Code: 20/9
  • 1455 XL (1981-1985)
  • Hydraulic system
  • Use: Normal
  • Capacity 34 liter
  • Check 200 hours
  • Change 800 hours
  • Code: 20/9
  • 1255 (1978-1981)
  • Hydraulic system
  • Use: Normal
  • Capacity 34 liter
  • Check 200 hours
  • Change 1000 hours
  • Code: 16/7
  • 1455 (1978-1981)
  • Hydraulic system
  • Use: Normal
  • Capacity 34 liter
  • Check 200 hours
  • Change 1000 hours
  • Code: 16/7

Additional Notes

  • All four configurations across the International Harvester 55/56 series share an identical 34-liter capacity for the combined transmission/hydraulic system, a figure that reflects the integrated nature of agricultural tractor hydraulics where a single fluid reservoir serves both the transmission and the implement hydraulic circuit.
  • The 1255 (1978-1981) and 1455 (1978-1981) both carry a 1000-hour change interval under normal use conditions, meaning fluid replacement is tied to operational hours rather than calendar time, which is standard practice for agricultural equipment.
  • The XL variants, the 1255 XL (1981-1985) and 1455 XL (1981-1985), have a reduced change interval of 800 hours under normal use conditions, 200 hours shorter than the non-XL counterparts despite sharing the same 34-liter capacity.
  • A 200-hour check interval applies uniformly across all four configurations, indicating that fluid level or condition inspection is scheduled at one-fifth the frequency of the full change interval on the non-XL models, and one-quarter on the XL models.
  • The 34-liter capacity across all configurations is a service fill figure, as the note specifies the transmission/hydraulic system as a whole rather than a dry-fill or overhaul scenario, which would typically be higher to account for residual fluid in coolers and lines.
  • The transition from the 1255 and 1455 to their respective XL variants in 1981 coincides with the shortening of the change interval from 1000 to 800 hours, a difference that applies consistently across both model designations within the XL generation.

Other Systems