How many quarts of transmission fluid does a 2018 GMC Sierra 1500 take?
The 2018 GMC Sierra 1500 typically requires about 12 to 13 quarts of transmission fluid for a full fill. For routine maintenance that drains only the pan and replaces the filter, you’ll usually swap around 5 to 7 quarts. Always verify the exact capacity for your specific build in the owner’s manual or via GM service specifications, since transmission choices and drivetrains can shift the requirement slightly.
Understanding the capacity figures
Transmission fluid capacity is usually reported as the total system fill. The Sierra 1500 commonly uses GM automatic transmissions from this era, and the total capacity tends to fall in the 12–13 quart range when a new filter is installed and the system is fully drained and refilled. If you are only draining the pan (a typical drain-and-fill), you will replace somewhat less fluid—roughly half to two-thirds of the total capacity depending on whether the torque converter is included in the drain.
Practical maintenance considerations
When performing a transmission service, account for variations from model to model and from transmission code. If your truck has a no-dipstick design or you are unsure of the level, consult the service manual or a dealer service tech. Always use the correct type of transmission fluid specified for your transmission and avoid overfilling, which can cause foaming and performance issues.
Summary
For a 2018 GMC Sierra 1500, plan on about 12–13 quarts for a full transmission fluid fill. A pan drain-and-fill typically replaces about 5–7 quarts. Always confirm with the exact model’s specifications before service.
