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2014-2018 GMC Sierra 1500 differential fluid & capacity

The Sierra 1500 has more than one differential, and they don't all take the same fluid. Each axle's exact gear oil spec and capacity is below, plus where to buy it.

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Front differential

Gear oil spec

SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401)

Front axle, 4WD trucks only. 2WD (RWD) trucks have no front axle. GM's ACDelco parts catalog (part 88900401, fitment-confirmed 2015-2024 Silverado 1500) separately lists this same fluid as 'GL-5 75W-90' — the manual's own prose just never states the GL rating.

Spec from the OEM (oem manual).

Find SAE 75W-90 Synthetic Axle Lubricant (GM Part No. 88900401) on Amazon
Where this came from
  • 2016 Chevrolet Silverado 1500 Owner's Manual — Recommended Fluids and Lubricants (Front Axle, Four-Wheel Drive) — source

Rear differential

Gear oil spec

SAE 75W-85 Synthetic Axle Lubricant (GM Part No. 19300457)

Rear axle, 1500 Series (this vehicle). The 2500/3500 Series uses the front-axle 75W-90 spec instead — a distinct table row not applicable to this 1500-series vehicle. GM's ACDelco parts catalog (part 19300457, fitment-confirmed 2014-2024 Silverado) separately lists this same fluid as 'GL-5 75W-85 High Efficiency' — the manual's own prose just never states the GL rating.

Spec from the OEM (oem manual).

Find SAE 75W-85 Synthetic Axle Lubricant (GM Part No. 19300457) on Amazon
Where this came from
  • 2016 Chevrolet Silverado 1500 Owner's Manual — Recommended Fluids and Lubricants (Rear Axle, 1500 Series) — source

Transfer case

Gear oil spec

DEXRON-VI Automatic Transmission Fluid

Transfer case, 4WD trucks only. Not a gear oil — same DEXRON-VI ATF as the 6L80 6-speed automatic transmission.

Spec from the OEM (oem manual).

Find DEXRON-VI Automatic Transmission Fluid on Amazon
Where this came from
  • 2016 Chevrolet Silverado 1500 Owner's Manual — Recommended Fluids and Lubricants (Transfer Case, Four-Wheel Drive) — source

Spec anchored to the OEM owner's manual; the capacity, when it carries the verified badge, is cross-checked against an independent source. Never changed by what an affiliate link pays us. Your owner's manual is always the final word — and if your axle has a locker or an option package, double-check the capacity for your exact build.