GM bulletin 18-NA-035
What it saysThis service bulletin provides information on a normal characteristic of a transmission that will not shift into overdrive range during cold ambient temperatures. NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Jan 23, 2024, received Feb 21, 2023, about the power train — 2 documents under this number. It names 48 model years across Chevrolet, GMC, Buick and Cadillac (2018–2024). 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 · Cadillac.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis service bulletin provides information on a normal characteristic of a transmission that will not shift into overdrive range during cold ambient temperatures.
Trouble codes it names: P0299 all 1 read from the document itself; NHTSA’s summary names none
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 18-NA-035 | Service bulletin | Jan 23, 2024 | 10250248 | PDF, 73 KB |
| 18-NA-035 | Service bulletin | Feb 1, 2023 | 10231891 | PDF, 72 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 16 model years
GMC 11 model years
Buick 5 model years
Cadillac 16 model years
and 8 more on this site: 2022 Cadillac XT5, 2021 Cadillac XT5, 2020 Cadillac XT5, 2024 Cadillac XT6, 2023 Cadillac XT6, 2022 Cadillac XT6, 2021 Cadillac XT6, 2020 Cadillac XT6.
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 48 model years this bulletin names have filed 4,860 complaints with NHTSA since 2015. 2,205 of them name Engine, 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 2018 Chevrolet Malibu, the 137 owners who gave an odometer reading for Engine reported it at a median of 50,000 miles. That figure is one model year’s, not the whole range this bulletin covers — medians from different model years are not averaged.
Engine problem loss of power intermittently no reverse. They replaced clutch parts seals, piston, rings, plates, and plates. Had Vehicle for about 22 days. Driving home after repairs completed. Cluster display- instrument panel went out. Called Dealer and Cadillac assistance. Says there nothing they can do until Cadillac releases a fix.
2024 Cadillac XT5 · Engine · filed with NHTSA Jun 24, 2024 · ODI 11596124
Car would stall suddenly mid intersection or street. There is an active recall for a fuel pump module with no known date of resolution. Fuel Pump Module would not provide adequate gas to the engine. This happened twice to me as I was driving on April 4th 2023. After speaking to Chevy & Dealership, there is not yet a fix to this problem.
2021 Chevrolet Equinox · Engine · filed with NHTSA Apr 21, 2023 · ODI 11518293
I was in slow traffic and my check engine light came on then the parking brake engaged. My car stopped and I could not disengage the parking brake so the car could shift gears. I turned my car off for several minutes. When I turned the car back on, the check engine light and parking brake turned off and I was able to shift gears again
2020 Cadillac XT4 · Power Train · filed with NHTSA Mar 27, 2025 · ODI 11651144
In depth: 2020 Chevrolet Equinox engine problems → · 2019 Chevrolet Equinox engine problems → · 2018 Chevrolet Equinox engine problems → · 2018 Chevrolet Equinox 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 group100 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, Buick and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 18-NA-035 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 18-NA-035 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 18-NA-035 cover?
The manufacturer filed it against 48 model years across 4 brands (Chevrolet, GMC, Buick and Cadillac): 2022 Buick Encore, 2021 Buick Encore, 2020 Buick Encore, 2019 Buick Encore, 2018 Buick Encore, 2024 Cadillac XT4 and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.