Audi A8L, S8L, 4N / 4NL (USA)

Transfer case fluid capacity & service interval

Audi A8L, S8L, 4N / 4NL (USA) transfer case fluid capacity ranges from 0,8 to 1 liter. Service intervals consist of checks every 20000 miles or 24 months. The data covers 4 configurations.

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

TypeSpecifications
  • S8L 4.0 TFSI quattro (420 kW) (2022- )
  • From automatic
  • Use: Normal
  • Capacity 1 liter (Initial fill)
  • Capacity 0,8 liter (Refill)
  • Check 20000 miles/ 24 months
  • A8L 55 TFSI quattro (250 kW) (2018- )
  • From automatic
  • Use: Normal
  • Capacity 1 liter (Initial fill)
  • Capacity 0,8 liter (Refill)
  • Check 20000 miles/ 24 months
  • A8L 60 TFSI quattro (337 kW) (2018-2022)
  • From automatic
  • Use: Normal
  • Capacity 1 liter (Initial fill)
  • Capacity 0,8 liter (Refill)
  • Check 20000 miles/ 24 months
  • S8L 4.0 TFSI quattro (420 kW) (2018-2022)
  • From automatic
  • Use: Normal
  • Capacity 1 liter (Initial fill)
  • Capacity 0,8 liter (Refill)
  • Check 20000 miles/ 24 months

Additional Notes

  • The transfer case fluid specifications listed here apply to the transferbox fed from the automatic transmission across all covered configurations of the Audi A8L, S8L, and 4N / 4NL (USA) lineup.
  • An initial fill capacity of 1 liter applies to all four configurations, reflecting the volume required when the transfer case is dry, such as after a complete overhaul or unit replacement.
  • A refill capacity of 0.8 liter is specified across all configurations, representing the smaller volume used when fluid is being replenished during a service procedure rather than a full drain and rebuild.
  • The 0.2-liter difference between the initial fill and refill figures accounts for residual fluid that remains in the transfer case housing and passages even after draining, which is a common characteristic of sealed or semi-sealed transfer case designs.
  • A check interval of 20,000 miles or 24 months under normal use conditions is uniform across the A8L 55 TFSI quattro, A8L 60 TFSI quattro, and both S8L 4.0 TFSI quattro entries.
  • The S8L 4.0 TFSI quattro (420 kW) appears under two separate year-range entries, one covering 2018-2022 and one starting from 2022, both carrying identical capacity and check interval figures.
  • Despite the power difference between the A8L 55 TFSI quattro at 250 kW and the A8L 60 TFSI quattro at 337 kW, the transfer case fluid capacities and service check intervals are identical between the two variants.
  • The S8L 4.0 TFSI quattro at 420 kW shares the same 1-liter initial fill, 0.8-liter refill, and 20,000-mile or 24-month check interval as the lower-output A8L variants, indicating no capacity or interval differentiation based on engine output across the covered range.

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