Mercedes-Benz GLS-Class, X166 (USA / CAN)

Transfer case fluid capacity & service interval

Mercedes-Benz GLS-Class, X166 (USA / CAN) requires transfer case fluid with a capacity range of 0,5 to 1,5 liters. The data covers 6 configurations.

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

TypeSpecifications
GLS 350 d 4MATIC, 166.823/824 (2017-2019)
  • Use: Normal
  • Capacity 0,5 liter
  • Capacity 1,5 liter (+ dual range)
GLS 450 4MATIC, 166.864 (2017-2019)
  • Use: Normal
  • Capacity 0,5 liter
  • Capacity 1,5 liter (+ dual range)
GLS 350 d 4MATIC, 166.823/824 (2015-2017)
  • Use: Normal
  • Capacity 0,5 liter
  • Capacity 1,5 liter (+ dual range)
GLS 450 4MATIC, 166.864 (2015-2017)
  • Use: Normal
  • Capacity 0,5 liter
  • Capacity 1,5 liter (+ dual range)
GLS 550 4MATIC, 166.873 (2015-2017)
  • Use: Normal
  • Capacity 0,5 liter
  • Capacity 1,5 liter (+ dual range)
GLS 63 AMG 4MATIC, 166.875 (2015-2019)
  • Use: Normal
  • Capacity 0,5 liter
  • Capacity 1,5 liter (+ dual range)

Additional Notes

  • Across all listed X166 configurations, the transfer case carries two distinct capacity figures: 0.5 liter and 1.5 liter. The 0.5-liter figure represents a standard service fill, while the 1.5-liter figure applies when the unit includes a dual-range assembly, which adds a secondary gear set requiring additional fluid volume to lubricate a larger internal cavity.
  • The dual-range transfer case variant triples the fluid requirement compared to the standard unit, moving from 0.5 liter to 1.5 liters. A technician identifying which capacity applies must first confirm whether the installed transfer case includes the dual-range feature before proceeding with a fluid service.
  • The Mercedes-Benz GLS 350 d 4MATIC (166.823/824) carries the same 0.5-liter and 1.5-liter capacity values across both the 2015-2017 and 2017-2019 production spans, indicating no change in transfer case fluid specification between those two periods for the diesel variant.
  • The GLS 450 4MATIC (166.864) shares identical transfer case capacity figures with the GLS 350 d across both of its listed production periods, despite the difference in engine type between the two models.
  • All six configurations listed, spanning the GLS 350 d, GLS 450, GLS 550, and GLS 63 AMG, carry the same 0.5-liter and 1.5-liter capacity values under normal use conditions. No configuration in the specifications deviates from these two figures.
  • The GLS 63 AMG 4MATIC (166.875) covers a single continuous span of 2015-2019 in the specifications, whereas the GLS 350 d and GLS 450 entries are each split into two overlapping periods. All entries share the same transfer case capacity values regardless of how the production years are segmented.

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