GM bulletin 24-NA-223
What it saysThis service bulletin informs the technician of an alternate lift procedure that has been developed when the lift plate does not fit the top of the transmission case for 6T30, 6T35, 6T40, 6T45, and 6T50 Transmissions. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Oct 10, 2024, received Nov 19, 2024, about the power train. It names 66 model years across Chevrolet, GMC and Buick (2016–2025). A service bulletin is not a safety recall: it is the manufacturer telling its dealers how to diagnose or repair a condition, and whether the work is paid for depends on the warranty in force. Quoting the number at a service desk can save a diagnosis.
One page for every brand it was filed under. Each brand’s bulletins: Chevrolet · GMC · Buick.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationWhat it applies to, as NHTSA’s summary states it — build dates and equipment as the manufacturer filed them. The dealer checks the VIN and the build date on the door jamb; a vehicle outside the window is not covered by this bulletin.
This service bulletin informs the technician of an alternate lift procedure that has been developed when the lift plate does not fit the top of the transmission case for 6T30, 6T35, 6T40, 6T45, and 6T50 Transmissions.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 24-NA-223 | Service bulletin | Oct 10, 2024 | 11010651 | PDF, 116 KB |
The summary is NHTSA’s abstract of the document, as filed under 49 CFR 579.5. One communication is usually filed as several documents — the bulletin, a dealer notice, an owner letter — and the number on any of them finds this page. A PDF link is shown only once NHTSA’s own server has been seen to serve that document; the rest are checked over the following nights. Quote the number at a service desk; it is what the dealer’s system is keyed on.
Model years it names
Source: as the manufacturer filed themChevrolet 35 model years
GMC 7 model years
Buick 24 model years
and 16 more on this site: 2017 Buick Encore, 2016 Buick Encore, 2020 Buick Envision, 2019 Buick Envision, 2018 Buick Envision, 2017 Buick Envision, 2016 Buick Envision, 2025 Buick Envista, 2024 Buick Envista, 2019 Buick LaCrosse, 2018 Buick LaCrosse, 2016 Buick LaCrosse, 2017 Buick Regal, 2016 Buick Regal, 2017 Buick Verano, 2016 Buick Verano.
A vehicle page’s bulletin list shows the newest few communications filed against that model year; the count there is every one.
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What owners reported
Source: NHTSA complaint databaseOwners of the 66 model years this bulletin names have filed 9,390 complaints with NHTSA since 2015. 1,610 of them name Power Train — the same broad component group this bulletin is filed under. NHTSA groups complaints coarsely, so that means the same area of the vehicle, not necessarily the same fault.
On the 2016 Chevrolet Malibu, the 111 owners who gave an odometer reading for Power Train reported it at a median of 43,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
1st occurence at approximately 37k miles on Vehicle has issue based on climate temperature sensor triggers a computer code 84 vehicle goes into limp mode to prevent engine failure however, this happens instantly no time to react and more than one occasion creating a hazardous driving situation in heavy traffic, vehicle also overheats…
2020 Chevrolet Sonic · Power Train · filed with NHTSA Mar 9, 2024 · ODI 11576430
The contact owns a 2019 Gmc Terrain. While driving, the transmission kept slipping between second and third gear and a grinding noise was heard. The contact stated that the vehicle was previously involved in a crash and the engine was replaced. The vehicle was taken back to the same dealer because the transmission continued to slip.
2019 GMC Terrain · Power Train · filed with NHTSA Nov 15, 2019 · ODI 11280304
At around 20 miles per hour, while accelerating, all torque is lost and the vehicle engine revs high. It takes a few seconds, then the transmission finally shifts into the next gear. This causes a big jolt. It is dangerous, all power is lost, then suddenly too much power is applied. This has happened since I purchased the vehicle.
2017 GMC Terrain · Power Train · filed with NHTSA Nov 25, 2019 · ODI 11282165
In depth: 2018 Chevrolet Equinox transmission and drivetrain problems → · 2019 Chevrolet Malibu transmission and drivetrain problems → · 2018 Chevrolet Malibu transmission and drivetrain problems → · 2017 Chevrolet Malibu transmission and drivetrain problems →
A complaint is one owner’s account, not a defect finding, and a bulletin is not a recall. Nothing here says this bulletin was issued because of these complaints, or that the repair it describes fixed them. Complaint files on this site begin in 2015.
More bulletins about the power train
Source: same model, same component group98 other manufacturer communications filed against these GM models under the same component group (power train), newest first. The eight newest are listed; the rest are on the Chevrolet list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| N252502890-01 | Service campaign | Aug 20, 2026 | Certain vehicles may have a condition in which the internal differential nut was cross threaded or missing during assembly. Dealers will rev… |
| N242471460-01 | Service campaign | Aug 20, 2026 | Certain vehicles may have been built with an Electric Drive Unit mounting bolt that is too long, causing damage to the Drive Unit case. Deal… |
| PIE0814B | Service bulletin | May 7, 2025 | This engineering information (EI) closure ends the need for requesting further information from technicians in regard to the Service AWD Lam… |
| PIP6036A | Service bulletin | Apr 2, 2025 | This Preliminary information communicates diagnostic aids for a surge or fishbite concern |
| 25-NA-001 | Service bulletin | Mar 13, 2025 | This service bulletin provides repair information to correct a customer concern of a transmission fluid leak. |
| PIE0814A | Service bulletin | Mar 12, 2025 | This engineering information (EI) is requesting information from technicians to perform the check list provided and contact the engineer lis… |
| 24-NA-232 | Service bulletin | Mar 7, 2025 | This technical bulletin provides repair information to correct a customer concern of Metallic Noise from Rear Differential on Acceleration. |
| PIP5966A | Service bulletin | Mar 2, 2025 | This Preliminary information communicates Diagnostic aids for a no start or DTC'S following a transmission replacement |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet, GMC and Buick, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 24-NA-223 a recall?
No. A service bulletin is a manufacturer communication filed with NHTSA under 49 CFR 579.5; a safety recall carries an NHTSA campaign number (two digits, a letter, six digits) and a federal duty to repair for free. Check the vehicle’s recalls by VIN at nhtsa.gov/recalls, or on its page here.
Is the 24-NA-223 repair free?
Not automatically. A service bulletin describes how to diagnose or repair a condition; who pays depends on the warranty in force, any extension, and the dealer. Quoting the number can save a diagnosis either way. Every GM warranty extension on file lists the ones GM has filed.
Which vehicles does 24-NA-223 cover?
The manufacturer filed it against 66 model years across 3 brands (Chevrolet, GMC and Buick): 2018 Buick Cascada, 2017 Buick Cascada, 2016 Buick Cascada, 2022 Buick Encore, 2021 Buick Encore, 2020 Buick Encore and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.