Why does my 2020 Silverado 1500 T1XX have a rough transmission shift?

Tools Required

• OBD-II Scanner
• Transmission fluid dipstick (if applicable)
• Funnel for adding transmission fluid
• Torque wrench
• Basic hand tools (sockets, wrenches)
• Transmission fluid (as specified in the owner’s manual)
• Multi-meter (for electrical inspection)

Repair Instructions

Step 1: Retrieve DTCs

1. Connect the OBD-II scanner to the diagnostic port under the dashboard.
2. Turn the ignition to the ON position (do not start).
3. Access the transmission control system and read any codes.
4. Make a note of any relevant codes for further investigation.

Step 2: Inspect Transmission Fluid

1. Park the vehicle on a level surface and engage the parking brake.
2. Start the engine and let it warm up to operating temperature.
3. Remove the transmission dipstick (if applicable) and wipe it clean.
4. Reinsert the dipstick and remove it again to check the level.
   • If low, add the recommended transmission fluid until the proper level is reached.
   • If fluid is dark or burnt, consider a fluid flush and filter change.

Step 3: Inspect TCM Connections

1. Locate the TCM, usually found near the transmission or under the dash.
2. Disconnect the wiring harness and inspect for corrosion or loose connections.
3. Reconnect and, if necessary, reprogram the TCM using a diagnostic tool.

Step 4: Check Transmission Mounts

1. Visually inspect the transmission mounts for cracks or excessive wear.
2. Use a torque wrench to ensure all mounting bolts are appropriately tightened.
3. Consider replacing damaged mounts to restore proper alignment.

Step 5: Test Drive and Recheck

1. After making any repairs, take the vehicle for a test drive to see if the issue persists.
2. Pay attention to shifts at various speeds and loads.

Conclusion

If the rough shifting persists after performing the above steps, a more in-depth inspection may be required, including:

• Internal transmission inspection (for band or clutch issues).
• Fluid pump and valve body examination.
• Possible replacement of the transmission if internal components are damaged.

For complex issues or if you’re unsure, it’s advisable to consult with a professional technician or a dealership for advanced diagnostics and repairs.