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

Automatic transmission fluid capacity & service interval

Mercedes-Benz GLS-Class, X166 (USA / CAN) automatic transmission fluid capacity ranges from 7,1 to 10 liters. Service intervals include 60000 miles or 77500 miles/60 months. The data covers 9 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 9 liter (Dry fill)
  • Change 77500 miles/ 60 months
  • Code: 722.9xx 7/1
GLS 350 d 4MATIC, 166.823/824 (2017-2019)
  • Use: Normal
  • Capacity 10 liter
  • Change 77500 miles/ 60 months
  • Code: 725.031 9/1
GLS 450 4MATIC, 166.864 (2017-2019)
  • Use: Normal
  • Capacity 9 liter (Dry fill)
  • Change 60000 miles
  • Code: 722.9xx 7/1
GLS 350 d 4MATIC, 166.823/824 (2015-2017)
  • Use: Normal
  • Capacity 9 liter (Dry fill)
  • Change 77500 miles/ 60 months
  • Code: 722.9xx 7/1
GLS 350 d 4MATIC, 166.823/824 (2015-2017)
  • Use: Normal
  • Capacity 10 liter
  • Change 77500 miles/ 60 months
  • Code: 725.031 9/1
GLS 450 4MATIC, 166.864 (2015-2017)
  • Use: Normal
  • Capacity 9 liter (Dry fill)
  • Change 60000 miles
  • Code: 722.9xx 7/1
GLS 550 4MATIC, 166.873 (2015-2017)
  • Use: Normal
  • Capacity 9 liter (Dry fill)
  • Change 60000 miles
  • Code: 722.9xx 7/1
GLS 63 AMG 4MATIC, 166.875 (2015-2019)
  • Use: Normal
  • Capacity 9 liter (Dry fill)
  • Change 60000 miles
  • Code: 722.905 7/1
GLS 63 AMG 4MATIC, 166.875 (2015-2019)
  • Use: Normal
  • Capacity 7,1 liter (Dry fill)
  • Change 60000 miles
  • Code: 722.931 7/1

Additional Notes

  • The Mercedes-Benz GLS-Class X166 automatic transmission fluid specifications cover multiple engine variants across the 2015-2019 model years, with all rows applying to normal use conditions.
  • A dry fill capacity value represents the total fluid volume required when filling a completely drained or rebuilt transmission, as opposed to a service fill, which accounts for residual fluid remaining after a drain. The 9-liter dry fill figure appears across the GLS 350 d 4MATIC, GLS 450 4MATIC, GLS 550 4MATIC, and GLS 63 AMG 4MATIC variants.
  • The GLS 350 d 4MATIC (chassis 166.823/824) carries two distinct capacity figures: a 9-liter dry fill and a separate 10-liter value. The 10-liter figure represents a higher total volume, consistent with a service or overfill specification that accounts for fluid retained in the torque converter and cooler lines during a complete fill procedure.
  • Both the 2015-2017 and 2017-2019 date ranges for the GLS 350 d 4MATIC share identical capacity values and change intervals, with the 9-liter dry fill and 10-liter service capacity paired with a 77,500-mile or 60-month interval under normal use.
  • The GLS 350 d 4MATIC carries a notably longer fluid change interval of 77,500 miles or 60 months compared to the 60,000-mile interval specified for the GLS 450 4MATIC, GLS 550 4MATIC, and GLS 63 AMG 4MATIC variants. The diesel-engined 350 d is also the only variant with a time-based interval component expressed in months alongside the mileage figure.
  • The GLS 63 AMG 4MATIC (chassis 166.875) is the only variant in the lineup with two different dry fill capacities listed: 9 liters and 7.1 liters. The lower 7.1-liter figure likely corresponds to a different transmission unit or a partial fill procedure specific to that configuration, both sharing the same 60,000-mile change interval.
  • The GLS 550 4MATIC (chassis 166.873) specifications cover only the 2015-2017 period, with a 9-liter dry fill capacity and a 60,000-mile change interval under normal use conditions.
  • The GLS 450 4MATIC (chassis 166.864) maintains consistent specifications across both the 2015-2017 and 2017-2019 date ranges, with a 9-liter dry fill capacity and a 60,000-mile change interval in both cases.

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