GM bulletin 23-NA-029
What it saysThis service bulletin provides a procedure to locate a possible shaft not inserted into the differential carrier that may have popped out to correct customer concerns of Transmission Grinds When Put into Gear, Slipping… NHTSA’s full summary ↓
GM filed this with NHTSA as a service bulletin dated Sep 7, 2023, received May 4, 2023, about the power train — 2 documents under this number. It names 5 model years across Chevrolet, GMC and Cadillac (2023). 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 · Cadillac.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationThis service bulletin provides a procedure to locate a possible shaft not inserted into the differential carrier that may have popped out to correct customer concerns of Transmission Grinds When Put into Gear, Slipping, No Movement When Shifted into Drive or Reverse.
Documents filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 23-NA-029 | Service bulletin | Sep 7, 2023 | 10242969 | PDF, 500 KB |
| 23-NA-029 | Service bulletin | Apr 11, 2023 | 10235621 | PDF, 500 KB |
What the document itself lists
The manufacturer titles it “Transmission Grinds When Put Into Gear, Slipping, No Movement When Shifted Into”.
Parts the bulletin names
| Part number | Description | Qty | Find it |
|---|---|---|---|
| 24290255 | CARR SUN | 1 | eBay Motors → |
| 24268389 | FLUID PUMP | 1 | eBay Motors → |
| 24267848 | CV HSG | 1 | eBay Motors → |
| 84990736 | — | — | |
| 84990735 | — | — | |
| 84990734 | — | — | |
| 11611965 | WHL DRV SHF | 2 | eBay Motors → |
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 8486258 | Front Differential Carrier Sun Gear Replacement | 8.4 hrs |
Read by machine from the document NHTSA serves (2 pages), read Sep 30, 2026. A part number is shown only where it matches GM’s own catalogue shape, an operation only with its code and time, and a description only where the reader got it whole; anything it could not settle is left out, and the PDF is the record. Times are the manufacturer’s warranty allowances, not a quote. Listings and prices on eBay Motors are the seller’s.
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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 2 model years
GMC 1 model year
Cadillac 2 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 5 model years this bulletin names have filed 218 complaints with NHTSA since 2015. 66 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.
7-8 mild transmission slips/sticking 3 MAJOR transmission events where the car seized up completely and stopped running. Almost felt like a car crash. Very abrupt stop and almost caused people behind us to rear end us Car is only 21 months old / 17,000 miles. Most recent was in early August. We have not driven car since out of fear
2023 Chevrolet Traverse · Power Train · filed with NHTSA Sep 18, 2024 · ODI 11615200
The contact owns a 2023 Cadillac XT5. The contact stated that upon shifting into reverse(R), the vehicle intermittently failed to respond. The contact stated that the failure had progressively worsened, and the vehicle responded after an extended period. The vehicle was taken to the dealer; however, the failure was not duplicated.
2023 Cadillac XT5 · Power Train · filed with NHTSA Oct 5, 2026 · ODI 11769127
The contact owns a 2023 Cadillac XT6. The contact stated while driving at an undisclosed speed, the vehicle lost motive power. The contact was able to pull to the shoulder of the roadway, where the vehicle failed to restart. No warning lights were illuminated. The vehicle was not taken to the dealer or an independent mechanic.
2023 Cadillac XT6 · Power Train · filed with NHTSA Aug 14, 2024 · ODI 11608604
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 group59 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 |
|---|---|---|---|
| N252502891-01 | 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… |
| 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… |
| 25-NA-001 | Service bulletin | Mar 13, 2025 | This service bulletin provides repair information to correct a customer concern of a transmission fluid leak. |
| 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. |
| PIP5981D | Service bulletin | Feb 26, 2025 | This Preliminary information communicates ordering process for the front and rear drive units are on restriction for all listed EV vehicles… |
| 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… |
| 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, GMC and Cadillac, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is GM 23-NA-029 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 23-NA-029 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 23-NA-029 cover?
The manufacturer filed it against 5 model years across 3 brands (Chevrolet, GMC and Cadillac): 2023 Cadillac XT5, 2023 Cadillac XT6, 2023 Chevrolet Blazer, 2023 Chevrolet Traverse, 2023 GMC Acadia. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.