Opel GT

Differential fluid capacity & service interval

Opel GT differential fluid capacity ranges from 0,65 to 1,1 liters. Service intervals include checks at 10000 km and changes at 1000 km. The data covers 4 configurations.

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

TypeSpecifications
  • GT 1.1 (1969-1973)
  • Rear
  • Use: Normal
  • Capacity 0,65 liter
  • Check 10000 km
  • GT 1.1 (1969-1973)
  • Rear
  • Use: First change only
  • Capacity 0,65 liter
  • Change 1000 km
  • GT 1.9 (1969-1973)
  • Rear
  • Use: Normal
  • Capacity 1,1 liter
  • Check 10000 km
  • GT 1.9 (1969-1973)
  • Rear
  • Use: First change only
  • Capacity 1,1 liter
  • Change 1000 km

Additional Notes

  • The Opel GT rear differential fluid capacity differs between the two engine variants, with the 1.1 producing a 0.65 liter fill and the 1.9 requiring a notably larger 1.1 liter fill, reflecting the physically larger differential unit paired with the bigger engine.
  • Both the GT 1.1 and GT 1.9 share a first change interval of 1,000 km, a break-in service designed to flush metal particles generated during initial gear wear from fresh differential components.
  • Under normal use conditions, both variants specify a check interval of 10,000 km rather than a full fluid change, indicating a level inspection rather than a drain-and-refill service at that mileage point.
  • The 0.65 liter capacity of the GT 1.1 rear differential is a relatively small fill volume, consistent with a compact rear axle unit found in lighter, smaller-displacement sport coupes of the era.
  • The 1.1 liter capacity recorded for the GT 1.9 rear differential represents a 69 percent larger fill volume compared to the 1.1 variant, a meaningful difference when sourcing fluid quantities for a service fill.

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