Steyr S21

Transfer case fluid capacity & service interval

Steyr S21 transfer case fluid capacity ranges from 4,5 to 6 liters. Service intervals include checks at 20000 km and changes at 40000 km or 12 months. The data covers 3 configurations.

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

TypeSpecifications
15S21 4x4 (1988-1996)
  • Use: Normal
  • Capacity 4,5 liter
  • Check 20000 km
  • Change 40000 km/ 12 months
  • Code: VG 1200
12S21 4x4 (1987-1988)
  • Use: Normal
  • Capacity 6 liter
  • Check 20000 km
  • Change 40000 km/ 12 months
  • Code: VG 1200
13S21 4x4 (1987-1988)
  • Use: Normal
  • Capacity 6 liter
  • Check 20000 km
  • Change 40000 km/ 12 months
  • Code: VG 1200

Additional Notes

  • The Steyr S21 transfer case fluid capacity varies by engine variant, with the 12S21 and 13S21 4x4 models requiring 6 liters, while the 15S21 4x4 calls for 4.5 liters.
  • A 6-liter transfer case fill is a notably large capacity, reflecting the physical size of the transferbox unit fitted to the 12S21 and 13S21 4x4 variants from 1987-1988.
  • The 15S21 4x4, covering 1988-1996, holds 4.5 liters in the transferbox, which is 1.5 liters less than the earlier 12S21 and 13S21 units.
  • All three variants share an identical check interval of 20,000 km, meaning fluid level inspection frequency does not differ across the S21 4x4 range.
  • The change interval across all S21 4x4 variants is set at 40,000 km or 12 months under normal use conditions, whichever comes first, combining a distance threshold with a fixed calendar limit.
  • A 12-month maximum change interval, regardless of distance traveled, is typical for vehicles that may accumulate low mileage yet still subject the fluid to thermal cycling and moisture ingress over time.
  • The check interval of 20,000 km falls at exactly the halfway point of the 40,000 km change interval, placing a fluid level inspection at the midpoint between each drain service across all three variants.

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