Diagsheet

2021 GMC Sierra 1500 · symptom sheet

Transmission shudders, slips or shifts hard

  • 41owner reports
  • 61,000median miles
  • $4,000median quote
  • 0involved a crash

Newest report Aug 5, 2026 · checked Sep 9, 2026

133 of the 552 complaints on this car are about the transmission and drivetrain. 41 of those describe transmission shudder.

Tick what matches of 41 reports

14
13
8
9
5

What got replaced

Owners who name the part that was replaced mention the torque converter (7 reports) and the valve body (4 reports).

Recalls and investigations

2 recalls on the transmission and drivetrain cover the 2021 model year. A recall on the same system isn't always the same failure, so read the defect text.

26V-083Feb 12, 2026
Power Train:Automatic Transmission:Control Module:Software

General Motors, LLC is recalling certain 2020 Chevrolet Silverado 2500, 3500, GMC Sierra 2500, 3500, and 2020-2022 Chevrolet Silverado 1500 and GMC Sierra 1500 vehicles that may have been repaired incorrectly under recall 24V797. The transmission control valve may fail and cause the rear wheels to lock up.

Risk and remedy
Risk: Rear wheel lock up increases the risk of a crash.
Remedy: Dealers will inspect the vehicles and update the transmission control software, free of charge. Owner notification letters were mailed March 6, 2026. Owners may contact GMC customer service at 1-800-462-8782 or Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N252516560. Vehicle Identification Numbers (VINs) involved in this recall became searchable on NHTSA.gov on February 12, 2026.
24V-797Oct 24, 2024
Power Train:Automatic Transmission:Control Module:Software

General Motors, LLC (GM) is recalling certain 2020-2022 Chevrolet Silverado 1500, 2500, 3500, GMC Sierra 1500, 2500, 3500, 2021 Cadillac Escalade, Escalade ESV, Chevrolet Tahoe, Suburban, GMC Yukon, and Yukon XL vehicles equipped with diesel engines. The transmission control valve may fail and cause the rear wheels to lock-up.

Risk and remedy
Risk: Rear wheel lock-up can increase the risk of a crash.
Remedy: Dealers will install new transmission control module software, free of charge. GM will provide a special coverage program to cover the repair of transmissions that are identified by the remedy software as containing a defective control valve. Owner notification letters were mailed December 12, 2024. Owners may contact GM customer service at 1-888-988-7267, Cadillac customer service at 1-800-458-8006, GMC customer service at GMC 1-800-462-8782 or Chevrolet customer service at 1-800-222-1020. GM's number for this recall is N242454440.

What owners paid

5 of the 41 reports quote a price. Each dot is one quote. The middle half runs $4,000 to $8,000.

$4,000$4,000$8,000
$0k$2k$4k$6k$8k

When it happens

The middle half of failures fell between 38,875 and 89,000 miles, from the 17 reports that gave a mileage.

221
322
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324
1725
1426

What owners wrote

“Vehicle began to slip or shift hard when putting it in gear or coming to a stop. The next morning the vehicle would not move when put in drive or reverse.”

Filed Feb 23, 2026

“Torque Converter failure confirmed by dealer: was driving at high way speeds when I noticed a slipping sensation from the transmission upon any sort of acceleration. No warning lights were illuminated or any symptoms leading up to the failure. This could have potentially caused me to lose any form of acceleration that would enable me to get off of the highway or away from a situation requiring sudden acceleration.”

Filed Sep 18, 2025

“Reached the 100,000 mile mark and the truck started shuddering. Took it to the dealership and they tell me the torque converter is coming apart and I need a new transmission.”

Filed May 31, 2025

“front idler gear for the transmission pump failed at 39500 miles. was fixed under GMC warranty. but now after getting the truck back the transmission has extremely harsh down shifts. still waiting for GM to figure out what to do next..”

Filed May 30, 2025 · 39,500 miles

Should you keep driving it?

This page can't tell you that. 0 of 41 reports involved a crash. Owners who file are the ones who had a bad experience, and nobody checks their reports. If the problem affects steering, braking, power or a fire risk, treat it as a safety fault and have it inspected before a long or high-speed drive.

File your own report with NHTSA. Complaint counts are how a problem gets an investigation.

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