Time: approx 3 hrs

Difficulty: moderate to difficult

Cost: $250-400

FUNCTION

An automatic transmission is a complex hydraulic pump with gears, clutches, bearings, valves, and actuators. The fluid in an automatic transmission is used to apply pressure, transfer torque, clean, cool, lubricate, and activate components. To perform its function, it needs to be in peak condition.

WHY SERVICE

Replacing the filter and fluid often can prevent one of the costliest repairs you can experience on a vehicle, the transmission. Heat, shearing forces, contaminates, and wear cause automatic transmission fluid to lose its protective properties. As the fluid additives and properties break down, temperatures increase, clutches wear, flow restricts, and components fail.

INTERVAL

GM recommends replacing the transmission fluid and filter every 45,000 miles, which falls in line with an industry standard of 30-60,000 miles, depending on driving conditions. Heavy start/stop traffic, hills, towing, extreme temperatures, etc warrant earlier service, while long-distance flat-driving can stretch out the interval.

Transmission fluid should be replaced on-condition. What does on-condition mean? New fluid is pink/red and opaque. Spent fluid is brown to black and has a horrible burnt smell. You obviously want to replace it before it gets to that point.

METHOD

On this vehicle, lowering the exhaust y-pipe is necessary to remove the pan and access the filter. Once the new filter is installed, it's important correctly check the fluid level.

On the 10L80, 10-speed  transmission, checking the fluid level requires getting the transmission fluid to the appropriate temperature. Watch the video below to see the complete service procedure and final fluid level check.

The process is the same for 2019-2024 Silverado, Suburban, Tahoe, Sierra, Tahoe, and Escalade with the 10L80 transmission. The transmission can be identified by scanning the QR code on the driver's door post. An RPO code of MQB designates the 10L80 transmission.