GM bulletin 18-NA-049
What it saysThis service bulletin advises the technician to replace the rear diff carrier if heavy corrosion caused noise, cracking and/or leaking to correct customer concerns of Clunk or Growl Noise Coming from Rear of Vehicle… NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Jan 31, 2024, received Feb 14, 2024, about the power train. It names 10 model years across Chevrolet and Buick (2016–2020). 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 · Buick.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis service bulletin advises the technician to replace the rear diff carrier if heavy corrosion caused noise, cracking and/or leaking to correct customer concerns of Clunk or Growl Noise Coming from Rear of Vehicle and/or Rear End Binding When Turning or Backing Up.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 18-NA-049 | Service bulletin | Jan 31, 2024 | 10250271 | PDF, 218 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 5 model years
Buick 5 model years
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 10 model years this bulletin names have filed 991 complaints with NHTSA since 2015. 103 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.
Engine light is on and vehicle is sluggish on hills and keeping up in traffic. Rpms run high if I try. Error code p0299 shows on scanning device- turbo under boost. I have 112,000 miles and need turbo replaced already. this vehicle is very well maintained. I did see a special notice for the GX version of this vehicle.
2020 Buick Encore · Power Train · filed with NHTSA Apr 23, 2024 · ODI 11584659
The contact's girlfriend owns a 2018 Buick Encore. The contact stated while his girlfriend was driving 35 mph, the vehicle inadvertently shifted to neutral and all the door latches unlocked independently. The contact stated that there was no warning light illuminated. The driver continued driving to her destination.
2018 Buick Encore · Power Train · filed with NHTSA Jul 26, 2021 · ODI 11426458
The contact owns a 2019 Buick Encore. The contact stated while the vehicle was in the park with the engine running, the contact felt a bump from the vehicle and the vehicle began to slowly move forward. The contact depressed on the brake pedal very hard for the vehicle to stop.
2019 Buick Encore · Power Train · filed with NHTSA Oct 19, 2021 · ODI 11437372
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 group48 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 |
|---|---|---|---|
| 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. |
| PIP5975A | Service bulletin | Feb 25, 2025 | This Preliminary information communicates information on what dealer technicians should due if they encounter a broken chain on a CVT transm… |
| 16-NA-019 | Service bulletin | Feb 12, 2025 | This informational buleltin provides information on Transmission Adaptive Functions and Correcting Low Mileage Harsh Shifts, Slips, or Flare… |
| PIP6032A | Service bulletin | Jan 29, 2025 | This Preliminary Information communication advises the technician on possible sources of transmission fluid leaks from the transmission oil… |
| 24-NA-242 | Service bulletin | Jan 11, 2025 | This service bulletin advises the technician to verify the latest software to the radio before just replacing the torque converter for the c… |
| PIP6036 | Service bulletin | Jan 9, 2025 | This Preliminary information communicates diagnostic aids for a surge or fishbite concern |
| 09-06-04-026Z | Service bulletin | Jan 9, 2025 | This bulletin provides information on identifying Non-GM Engine Calibrations for Gasoline Engines using the Tech 2 or GDS 2. |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Chevrolet and Buick, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 18-NA-049 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-049 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-049 cover?
The manufacturer filed it against 10 model years across 2 brands (Chevrolet and Buick): 2020 Buick Encore, 2019 Buick Encore, 2018 Buick Encore, 2017 Buick Encore, 2016 Buick Encore, 2020 Chevrolet Trax and more. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.