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my GMC Sierra T1XX (2019-Present) has a delay in shifting gears what's going on - GMC Sierra
Home/Cars/GMC/Sierra/T1XX (2019-Present)/my GMC Sierra T1XX (2019-Present) has a delay in shifting gears what's going on

my GMC Sierra T1XX (2019-Present) has a delay in shifting gears what's going on

GMC Sierra T1XX (2019-Present)

Error Codes
2-4 hours
Time
medium
Difficulty
medium
Severity
Navigation
ProblemSymptomsDiagnosisSolution
ProblemSymptomsDiagnosisSolution
3 min read
574 words

Problem Statement

Learn how to diagnose and fix transmission delay issues in GMC Sierra T1XX (2019-Present). Step-by-step guide with symptoms, diagnostics, and repairs.

Affected Component
Transmission
Estimated Time
2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

  • •Disconnect the battery before working on electrical systems.
  • •Ensure the vehicle is securely raised and supported before working underneath it.

Symptoms

  • •Delay in shifting gears during acceleration
  • •Slipping or harsh shifting between gears
  • •Increased engine RPM before shifting occurs
  • •Check engine light illuminated
  • •Poor fuel economy

Diagnostic Steps

  1. 1
  2. 2
  3. 3
  4. 4
  5. 5
  6. 6

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

  • ✓Test the affected component to ensure it functions correctly
  • ✓Check for any error codes or warning lights
  • ✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

  • •Follow the manufacturer's recommended maintenance schedule
  • •Address warning signs early before they develop into major issues
  • •Use quality parts and fluids recommended for your vehicle
  • •Keep detailed records of all repairs and maintenance

Tools & Equipment Required

  • •OBD-II scanner
  • •Socket set
  • •Torque wrench
  • •Multimeter
  • •Transmission fluid pump
  • •Drain pan

Parts Required

  • •Transmission fluid
  • •Transmission filter
  • •Throttle position sensor (if replacement needed)
  • •Transmission pan gasket

Additional Information

Affected Component
Transmission
Estimated Time
2-4 hours
Difficulty
medium
Severity
medium
Tools Required
6 items
Parts Required
4 items

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Solution
1. Preparation
  • Gather necessary tools and parts.
  • Disconnect the battery to ensure safety during repairs.
2. Check Transmission Fluid
  1. Locate the transmission dipstick (if equipped).
  2. Remove the dipstick and wipe it clean.
  3. Reinsert the dipstick and remove it again to check the fluid level.
  4. If the fluid is low, top it off with the recommended transmission fluid (consult owner’s manual).
  5. Inspect the fluid color and smell; if it is dark or burnt, consider a fluid change.
3. Inspect Transmission Control Module (TCM)
  1. Locate the TCM in the vehicle (refer to service manual for exact location).
  2. Disconnect the TCM harness connector.
  3. Inspect the connector and pins for corrosion or damage.
  4. Reconnect and test the TCM using a scan tool to ensure it is functioning correctly.
4. Test and Replace Throttle Position Sensor (if necessary)
  1. Locate the throttle position sensor.
  2. Use a multimeter to check the voltage output of the TPS while operating the throttle.
  3. If readings are inconsistent or out of specifications, replace the TPS.
    • Disconnect the electrical connector.
    • Remove the TPS mounting screws and take it out.
    • Install the new TPS, reconnect the electrical connector, and test for proper operation.
5. Transmission Fluid Change (if required)
  1. Raise the vehicle securely on jack stands.
  2. Place a drain pan under the transmission pan.
  3. Remove the transmission pan bolts and carefully lower the pan.
  4. Drain the old fluid and replace the transmission filter.
  5. Reinstall the pan with a new gasket and torque bolts to manufacturer specifications (usually around 10-14 ft-lbs).
  6. Refill with the appropriate transmission fluid through the dipstick tube.