Opel Diplomat B

Differential fluid capacity & service interval

Opel Diplomat B uses differential fluid with a capacity of 1,3 liters. Service intervals occur every 10000 km or 6 months. Data covers 6 configurations.

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

TypeSpecifications
  • Diplomat B 2.8 E (1969-1977)
  • Rear
  • Use: Normal
  • Capacity 1,3 liter
  • Check 10000 km/ 6 months
  • Diplomat B 2.8 E (1969-1977)
  • Rear, limited slip
  • Use: Normal
  • Capacity 1,3 liter
  • Check 10000 km/ 6 months
  • Diplomat B 2.8 HC (1969-1977)
  • Rear
  • Use: Normal
  • Capacity 1,3 liter
  • Check 10000 km/ 6 months
  • Diplomat B 2.8 HC (1969-1977)
  • Rear, limited slip
  • Use: Normal
  • Capacity 1,3 liter
  • Check 10000 km/ 6 months
  • Diplomat B 2.8 S (1969-1977)
  • Rear
  • Use: Normal
  • Capacity 1,3 liter
  • Check 10000 km/ 6 months
  • Diplomat B 2.8 S (1969-1977)
  • Rear, limited slip
  • Use: Normal
  • Capacity 1,3 liter
  • Check 10000 km/ 6 months

Additional Notes

  • The Opel Diplomat B carries a rear differential fluid capacity of 1.3 liters across all 2.8-liter variants covered in the specifications, spanning the 2.8 E, 2.8 HC, and 2.8 S engine configurations from 1969-1977.
  • The 1.3-liter figure represents a service fill capacity, meaning the volume of fluid required when refilling the differential during routine maintenance rather than a full overhaul procedure.
  • Each variant specifies a check interval of 10,000 km or 6 months, whichever comes first, applied under normal use conditions.
  • The dual-format interval of 10,000 km or 6 months means fluid condition is evaluated on both a distance and a time basis, so a vehicle driven infrequently would still reach a service point at the 6-month mark regardless of mileage accumulated.
  • All three engine variants, the 2.8 E, 2.8 HC, and 2.8 S, share an identical rear differential capacity and check interval, indicating no differentiation in differential specification across the 2.8-liter engine lineup.
  • Within each engine variant, the standard rear differential and the limited-slip rear differential share the same 1.3-liter capacity and 10,000 km / 6-month check interval, despite the limited-slip unit being a mechanically distinct assembly requiring a specific fluid type suited to its clutch pack or friction components.

Other Systems