2020 Chevrolet Silverado 3500 problems

Filed Aug 22, 2026 · OR

Transmission will not shift into high gears throws engine code

Filed Aug 17, 2026 · Transmission · AZ

VIN: [XXX] Make/Model/Year: 2020 Chevrolet Silverado 3500HD, Duramax L5P, Allison 10L1000 Recall: N242454440 / N242454441 (the federal safety agency 24V797) Description: Vehicle had N242454440 completed May 2026 (TCM software update for harsh shift / wheel lockup). On XXX at 103k miles, vehicle exhibited same defect: harsh downshift 8th-9th gear, CEL on. Diagnosed as TCM failure per N242454441. Vehicle at O'Reilly Chevrolet Tucson since XXX (18 days out of service as of XXX). Dealer states TCM on national backorder, SPAC ticket opened, no ETA. Dealer denied courtesy transportation stating out of warranty at 103k, despite recall being federal safety recall with 15yr/150k special coverage. This is failure of remedy for safety recall that can cause momentary rear wheel lockup. No parts available, no transportation provided. What I want: GM to provide rental coverage and expedite TCM repair per recall obligations. Owner: [XXX], [XXX], [XXX], [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 6, 2026 · Transmission · VA

Since buying the vehicle I’ve had issues with the truck going into limp mode with codes p0700 as well as p0747. I have taken it to the dealership twice now, when it has arrived the codes were no longer there. Every time the truck went into limp mode the transmission would get stuck into 5th gear stuck at 45 mph. The problem with the truck started at 48,000 miles, the truck currently has 60,000 miles and the problem has been more active. With the dealership not wanting to resolve the issue the truck was taken to another shop to try to fix the transmission.

Filed Jul 1, 2026 · Fuel system · GA

The fuel pump driver module. I filled my truck up with diesel and it drove home fine. Later that afternoon left the house and got half mile down the road and the truck just shut off with no warning lamps or message. When this happened, you could not steer the truck and the brakes barley worked, now after the truck cut off a message came to shift in neutral. I was lucky no one was on the road at that time. Now had this happened the day before when I was coming home pulling a 40ft fifth wheel, this could have been catastrophic. When this fuel pump module goes out you have no warning the truck cuts off and you have no steering or brakes. This module needs to be recalled, and something else done to have some kind of warning before everything shuts off. People get these trucks to pull things and sooner than later Chevrolet will be answering to a fatality due to this fuel module, this does not need to be ignored till this happens.

Filed Apr 13, 2026 · Transmission · WI

The transmission, without warning, intermittently locks the rear wheels when towing a 13,500 lb 5th wheel RV. It occurs when going uphill and the transmission downshifts to maintain torque. The "D" on the gear indicator on the dashboard also flashes 3-5 times. This is a known issue with the Allison approved (but GM made) transmission from model year 2020 to 2022 (the federal safety agency 24V‑797) and is to be under extended warranty. We brought it to a Chevy dealer who kept from March 24 to April 9, without any resolution as they could not replicate the error which only happens under load travelling uphill. I also openedd a case with Chevrtolet Customer Service, who apparently does not have any ability to compel GM corporate techs or dealerships to fix the issue described without an error code. Historically, the truck throws error codes routinely and we have spent several thousand dollars trouble shooting the communication issues, also without resolution. We live in Wisconsin and were on vacation near Los Angeles, CA and had to transport it back home, leaving our RV in storage in California. At present, the only path to repairing the truck is to pay for the transmission repair ourselves. GM still does not have a long term solution for the tranmissions they now manufacture.

Filed Mar 17, 2026 · Transmission · TN

This is a supplemental update to complaint #XXX filed February 7, 2026, regarding my 2020 Chevrolet Silverado 3500HD Diesel (VIN: [XXX] ). The vehicle experienced a sudden and complete loss of propulsion on January 21, 2026, consistent with the defect mechanism described in Recall 24V797. Recall software was installed May 27, 2025. Failure occurred eight months later with no warning. GM's response has been as follows: A Field Technical Service Engineer made a remote determination that the failure did not match the recall without physically inspecting the transmission. GM Executive Resolution required teardown at customer expense with no reimbursement guarantee. The authorized dealership (Dave Kirk Chevrolet, Crossville TN) declined to perform a documented inspection -- citing unwillingness, not inability. Written refusal was withheld for over one week. GM's Executive Resolution liaison admitted she had known of the refusal and withheld that information from me, directly delaying my ability to act. The final repair order (RO 50479) contains a self-documented notation: "Added tech notes 3/16/26" -- eight weeks after the January inspection. The transmission pan was fully removed, fluid was discarded, and pan bolts were not reinstalled. The only photograph provided does not reflect as-found conditions. Evidence integrity has been materially compromised. The vehicle has been without propulsion since January 21, 2026. Full chronology, documentation, and supporting evidence are attached. INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Feb 6, 2026 · Transmission · TN

The vehicle experienced a sudden loss of propulsion while driving at highway speed after normal operation. The transmission began slipping and then would no longer engage gears. The vehicle had to be pulled over and towed. This vehicle is subject to GM Recall N242454440 related to a known transmission control valve defect that can cause loss of propulsion. I was not notified of this recall by GM and discovered it independently. Once aware, I completed the recall software update. After the failure, the dealer documented pressure control fault codes (P0746 and P0798), burnt transmission fluid, and internal debris, and recommended full transmission replacement. I requested that GM evaluate whether this failure is related to the known defect addressed by the recall and Special Coverage N242454441. GM acknowledged my escalation request but did not schedule an inspection, did not contact the dealer, and closed the case without performing a causation review. The vehicle remains disabled, no technical inspection has occurred, and I am incurring rental costs. I am reporting this as a safety-related failure and recall handling concern.

Filed Jan 30, 2026 · Transmission · IA

While driving at highway speed in my 2020 Chevrolet Silverado 3500 Duramax, the transmission suddenly failed and locked up without warning. This caused an immediate loss of vehicle function and created a dangerous situation while traveling in traffic. I had my two children in the vehicle at the time. I was able to safely maneuver the truck to the shoulder, but the vehicle was no longer operable and required towing. This failure occurred only a few months after a transmission replacement and follows prior transmission repairs, including a valve body replacement performed by a GM dealership. This is a repeat transmission failure and presented a serious safety risk due to the sudden nature of the failure at highway speed.

Filed Sep 30, 2025 · Transmission · UT

On [XXX], while driving ~65 mph, my 2020 Chevrolet Silverado 2500HD Duramax experienced a sudden transmission lock-up, nearly causing a crash. The event caused severe internal transmission damage, leaving the truck unsafe and inoperable. This is the exact defect described in the federal safety agency Recall #24V‑797 (GM Recall N242454440), which states that valve body wear can cause rear-wheel lock-up. My truck stored P0700 and P2820, which directly indicate a valve body failure. GM refuses to repair my vehicle under Special Coverage N242454441 (15 years/150,000 miles) because code P0747 did not set, even though my failure clearly matches the defect. I requested a hydraulic valve body leak test, the only way to confirm the defect, but the dealer refused, saying they only scan codes. GM must perform this test at no cost, as required by federal recall laws. GM’s denial leaves a known safety defect unrepaired, violating federal recall obligations and putting drivers at risk. the federal safety agency action is needed to require GM to repair vehicles like mine, regardless of which DTC is stored. VIN: XXX Mileage at failure: 145,560 Dealer: Ken Garff Chevrolet – American Fork, Utah GM Case #: [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

Filed Jul 30, 2025 · Visibility · GA

I am writing to formally submit a complaint regarding a recurring and unresolved mechanical defect in my 2020 Chevrolet Silverado 2500HD, which I believe may constitute a widespread safety and reliability concern affecting this vehicle model. Since I purchased the truck in June 2020, I have experienced seven (7) failures of the air conditioning compressor system. The first six failures were repaired at authorized Chevrolet service centers, and the vehicle is currently undergoing a seventh replacement. All repairs have been documented and performed through Chevrolet dealerships, and I am attaching copies of the service repair orders for your reference. On July 24, 2025, a Chevrolet Customer Assistance representative, Chana Padgett, confirmed to me that the A/C compressor has been on national backorder, which I was told was due to the frequency of failures reported in 2020 Silverado 2500HD models nationwide. This points to a systemic defect, not an isolated case. The vehicle now has approximately 54,000 miles, and the repeated failures have resulted in: Significant loss of use of the vehicle Extended downtime due to backordered parts Decreased resale value and overall reliability Excessive repair costs, inconvenience, and loss of productivity The continued failure of a critical component like the A/C compressor affects not only driver comfort, but also visibility and ventilation—especially in southern states during peak summer months—posing potential safety hazards. I urge the federal safety agency to initiate an investigation into this matter to determine if a recall or further corrective action by General Motors is warranted for the 2020 Silverado 2500HD model line.