NHTSA Preliminary Evaluation: 6L90 Transmission Failure in Chevrolet Express Cutaway Van (PE23-016)

PE23-016 at a glance

What is NHTSA investigating in the Chevrolet Express Cutaway Van?

From NHTSA’s investigation summary:

The Office of Defects Investigation (ODI) opened this Preliminary Evaluation (PE) after receiving one Vehicle Owner Questionnaire (VOQ) complaint related to four school buses built on General Motors (GM) van chassis.

The VOQ alleged transmission failure resulting in a loss of all forward gear.

In ODI's pre-investigative discussions with GM, ODI learned that valve body separator plates had been machined out of tolerance during production periods between October 2016 to April 2017 and February 2021 to April 2021.

This out of tolerance machining may create excessive wear to the valve body check balls, possibly resulting in an inability to engage drive or reverse.

The potential loss of drivability only begins when shifting from a park or neutral transmission selection and does not occur during a functional drive cycle.

The average failure mileage of vehicles which experienced this condition is within warranty and related claims or complaints did not include any accidents, injuries, or fatalities.

After discussions with GM, Technical Service Bulletin (TSB) 23-NA-142 (NHTSA ID number 10243753) was released in September 2023.

This technical service bulletin provides a procedure for technicians to replace the forward check ball and separator plate if found to be the cause of a customer's concern.

During the course of the investigation, GM also released a Customer Satisfaction Program (CSP) N232428780 (NHTSA ID 10253316) in February 2024, to notify school bus and ambulance fleets of the concern and to proactively mitigate the risk in these essential-operation vehicles.

Recently, ODI contacted multiple school bus fleets, verifying that there have not been any stranded buses mid-route from this condition.

Additionally, ODI has not received any additional VOQ complaints since the opening of this investigation.

Based on the available information, including GM's TSB and CSP, this PE is closed.

The closing of this investigation does not constitute a finding by NHTSA that a safety-related defect does not exist.

The Agency reserves the right to take additional action if warranted by future circumstances.

To review the ODI report cited in the Closing Resume ODI Report Identification Numbers document, go to NHTSA.gov.

What is a preliminary evaluation?

Preliminary Evaluation is the first stage of a federal defect investigation. NHTSA reviews complaints, crash reports and manufacturer data to decide whether a safety defect may exist. It can close with no action, be upgraded to an engineering analysis, or end with a recall.

Did this investigation lead to a recall?

NHTSA closed this investigation on January 10, 2025 without listing a recall. That can mean NHTSA did not find a safety defect it could prove, or that the manufacturer addressed the issue another way. A closed investigation does not mean owners have no lemon law claim if the problem keeps happening.

Which vehicles are part of this investigation?

What are Chevrolet Express Cutaway Van owners reporting to NHTSA?

NHTSA’s public database lists 7 owner complaints filed since 2020 for the vehicles in this investigation (all components). Complaints are unverified owner reports.

What should owners do?

1. Check your VIN at nhtsa.gov/recalls for any open recall on your vehicle.
2. If you have the problem NHTSA is investigating, take the vehicle to a dealer now and get a repair order, even if the dealer cannot find anything.
3. Keep a log of every time the problem happens: date, mileage and what happened. Photos and videos help.
4. File your own complaint at nhtsa.gov/report-a-safety-problem. Owner complaints are what start and expand investigations.
5. If the problem keeps coming back, talk to a lemon law attorney.

Recalls on the same vehicles

• 2025-2026 Chevrolet Express Steering Recall (26V399)
• 2026 Chevrolet Express Steering Column Recall (26V345)
• 2025-2026 Chevrolet Express Tire Sidewall Recall (26V127)
• 2025 Chevrolet Express Head Restraint Recall (25V299)
• 2025 Chevrolet Express Body Door Recall (25V087)
• 2023 Chevrolet Express Drivetrain Software Recall (24V839)
• 2021-2023 GMC Savana Wiring Recall (23V247)
• 2021 Chevrolet Express Battery Cable Recall (21V189)
• 2021 Chevrolet Express Tire Recall (21V115)

Can a recall or defect investigation make my car a lemon in California?

Not by itself. What matters is whether a covered defect keeps coming back or keeps your vehicle at the dealer, and a federal investigation or recall is strong evidence that the problem is real.

Under California’s Song-Beverly Consumer Warranty Act, a manufacturer that cannot fix a warranty defect that substantially impairs a vehicle’s use, value or safety within a reasonable number of attempts may have to repurchase or replace it (Civ. Code 1793.2(d)). Within the first 18 months or 18,000 miles, the law presumes a reasonable number of attempts after two repairs of a defect likely to cause death or serious injury, four repairs of the same defect, or more than 30 days out of service (Civ. Code 1793.22(b)).

An owner who prevails can recover reasonable attorney fees and costs from the manufacturer (Civ. Code 1794(d)). You pay nothing, win or lose. We are paid only if you win, and the manufacturer pays our fees, including in settlements. If a case is lost, our firm covers the costs.

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