my GMC Sierra transmission slips when accelerating what's wrong

Learn how to diagnose and fix transmission slippage during acceleration in GMC Sierra. 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 cool.
• Disconnect the battery to prevent any electrical issues during repair.

2. Check and Replace Transmission Fluid

• Sub-steps:

  • Remove the transmission dipstick and check fluid level; add fluid if low.
  • If fluid is dirty or burnt, drain the old fluid by removing the transmission pan.
  • Replace the transmission fluid with manufacturer-recommended fluid and refill to the correct level.

• Tools Required: Transmission fluid, funnel, drain pan, socket set.

3. Replace Transmission Filter

• Sub-steps:

  • Remove the transmission pan bolts and gently lower the pan, allowing old fluid to drain.
  • Remove the old transmission filter and replace it with a new one, ensuring it is seated correctly.
  • Clean the transmission pan and gasket surfaces before reinstalling the pan.

• Tools Required: Socket set, gasket scraper, new transmission filter, new pan gasket.

4. Inspect and Repair Transmission Components

• Sub-steps:

  • If the issue persists, conduct a visual inspection of the valve body and solenoids for damage or wear.
  • Replace any damaged components as needed.
  • Reconnect the battery and perform a transmission relearn procedure if applicable.

• Tools Required: Torque wrench (for pan reinstallation), service manual for specifications.