my GMC Sierra T1XX (2019-Present) is leaking transmission fluid, what should I do?

Learn how to diagnose and fix transmission fluid leaks in GMC Sierra T1XX. Step-by-step guide with diagnostic procedures and repair instructions.

Solution

1. Preparation

• Gather tools and parts needed for the repair.
• Ensure the vehicle is parked on a level surface and the engine is off.
• Disconnect the battery to avoid electrical shorts.

2. Raise Vehicle

• Use a jack to lift the front of the vehicle and secure it with jack stands.
• Ensure it's stable before proceeding.

3. Inspect and Replace Transmission Pan Gasket

• Tools Required: Socket set, torque wrench, gasket scraper, fluid catch pan.
• Remove the transmission pan bolts using a socket wrench.
• Carefully lower the pan and allow any remaining fluid to drain into the catch pan.
• Inspect the old gasket for damage; clean the mating surfaces with a gasket scraper.
• Install the new gasket on the transmission pan.
• Reattach the transmission pan and torque the bolts to the manufacturer's specifications (typically around 10-12 ft-lbs).

4. Replace Transmission Lines (if necessary)

• Tools Required: Wrench set, line wrenches, fluid catch pan.
• Identify the leaking transmission line and remove the appropriate fittings using line wrenches.
• Install the new transmission line and ensure all connections are tight to prevent future leaks.

5. Refill Transmission Fluid

• Parts Required: Transmission fluid (consult owner's manual for type and amount).
• Using a funnel, refill the transmission fluid through the dipstick tube.
• Start the engine and let it run for a few minutes, cycling through the gears to ensure fluid circulates.