my Toyota Highlander Third Generation (2014-2019) has a harsh shifting transmission, what to do

Solution

1. Preparation

• Tools Required: OBD-II scanner, socket set, transmission fluid dipstick, funnel, transmission fluid, safety goggles, gloves.
• Ensure the vehicle is parked on a level surface and the parking brake is engaged.
• Disconnect the battery to prevent electrical issues during repairs.

2. Check and Replace Transmission Fluid

• Sub-steps:
  1. Locate the transmission fluid dipstick and remove it to check fluid level.
  2. If the level is low, add compatible transmission fluid until it reaches the recommended level.
  3. If fluid is dark or has a burnt smell, it should be replaced.
     • Remove the transmission drain plug using a socket set.
     • Allow old fluid to drain completely into a container.
     • Replace the drain plug and torque to manufacturer specifications (typically around 30-40 ft-lbs).
     • Refill with the appropriate type and amount of new transmission fluid through the dipstick tube using a funnel.

3. Inspect and Replace Transmission Filter (if applicable)

• Sub-steps:
  1. Locate the transmission pan and remove the bolts using a socket set.
  2. Carefully lower the pan and remove the old filter.
  3. Install the new filter and ensure it is seated properly.
  4. Clean the transmission pan and replace the gasket if necessary.
  5. Reattach the pan, torque the bolts to manufacturer specifications.

4. Check Electrical Connections

• Sub-steps:
  1. Inspect the wiring harness connected to the TCM for any signs of wear or damage.
  2. Clean any corrosion from the connectors.
  3. Reconnect the wiring securely.

5. Reconnect Battery and Test

• Reconnect the battery terminals.
• Start the vehicle and allow it to warm up.
• Test drive the vehicle to monitor transmission performance.