Opel Diplomat A

Differential fluid capacity & service interval

Opel Diplomat A differential fluid capacity ranges from 1,3 to 1,5 liters. Service intervals include 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 A 2.6 (1964-1968)
  • Rear
  • Use: Normal
  • Capacity 1,4 liter
  • Check 10000 km
  • Diplomat A 2.8 (1964-1968)
  • Rear
  • Use: Normal
  • Capacity 1,4 liter
  • Check 10000 km
  • Diplomat A 2.8 HL (1964-1968)
  • Rear
  • Use: Normal
  • Capacity 1,3 liter
  • Check 10000 km/ 6 months
  • Diplomat A 2.8 HL (1964-1968)
  • Rear, limited slip
  • Use: Normal
  • Capacity 1,3 liter
  • Check 10000 km/ 6 months
  • Diplomat A 4.6 V8 (1964-1968)
  • Rear
  • Use: Normal
  • Capacity 1,5 liter
  • Check 10000 km/ 6 months
  • Diplomat A 4.6 V8 (1964-1968)
  • Rear, limited slip
  • Use: Normal
  • Capacity 1,5 liter
  • Check 10000 km/ 6 months

Additional Notes

  • The Opel Diplomat A rear differential capacity varies by engine variant, ranging from 1.3 liters in the 2.8 HL to 1.5 liters in the 4.6 V8, with the 2.6 and 2.8 sitting at an intermediate 1.4 liters.
  • The 2.6 and 2.8 variants share an identical rear differential capacity of 1.4 liters under normal use conditions, with a check interval set at 10,000 km.
  • The 2.8 HL rear differential, whether in standard or limited slip configuration, holds 1.3 liters — the smallest capacity across all Diplomat A variants listed — and carries a check interval of 10,000 km or 6 months, whichever comes first.
  • The limited slip differential in the 2.8 HL shares the same 1.3-liter capacity and 10,000 km / 6-month check interval as the standard rear differential in the same variant, indicating no capacity difference between the two differential types at that engine level.
  • The 4.6 V8 rear differential holds 1.5 liters under normal use conditions, the largest rear differential capacity among all Diplomat A configurations in the 1964-1968 range.
  • Both the standard and limited slip rear differentials on the 4.6 V8 share the same 1.5-liter capacity and a check interval of 10,000 km or 6 months, mirroring the dual-entry pattern seen in the 2.8 HL.
  • The 2.6 and standard 2.8 variants specify only a distance-based check interval of 10,000 km, without the additional 6-month time condition that applies to the 2.8 HL and 4.6 V8 rear differentials.

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