Mercedes-Benz service campaign NCU - 2024120012
What it saysFor basic data of model 254 with M254, see AR27.10-P-0005MRW For basic data on transmission oil level test routine, see AR27.00-P-0270EWN. NHTSA’s full summary ↓
Mercedes-Benz filed this with NHTSA as a service campaign dated Dec 20, 2024, received Jan 2, 2025, about the power train. It names 1 model year (2024). A service campaign is not a safety recall — there is no NHTSA campaign number and no federal requirement — but it is usually work the manufacturer pays for on the vehicles it names; the dealer checks the VIN against the manufacturer’s list.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationReplace automatic transmission. For basic data of model 254 with M254, see AR27.10-P-0005MRW For basic data on transmission oil level test routine, see AR27.00-P-0270EWN.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| NCU - 2024120012 | Service campaign | Dec 20, 2024 | 11012132 | PDF, 34 KB |
What the document itself lists
Part the bulletin names
| Part number | Description | Qty |
|---|---|---|
| A 002 989 06 03 | Transmission oil | 13 |
Read by machine from the document NHTSA serves (1 page), read Sep 30, 2026. A part number is shown only where it matches Mercedes-Benz’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.
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 themA 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 1 model year this bulletin names have filed 31 complaints with NHTSA since 2015. 7 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.
While driving my 2024 Mercedes-Benz GLC 300 on California highways, the vehicle has repeatedly experienced sudden uncontrolled deceleration, unexpected transmission downshifts into 2nd gear, severe transmission jerking, and complete loss of accelerator response.
2024 Mercedes-Benz GLC-Class · Power Train · filed with NHTSA May 27, 2026 · ODI 11740380
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 group25 other manufacturer communications filed against the Mercedes-Benz GLC-Class under the same component group (power train), newest first. The eight newest are listed; the rest are on the Mercedes-Benz list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| LI27.00-P-073124 | Service bulletin | Sep 26, 2026 | Complaint Customer complaints relating to automatic transmission 725.0 (NAG3 Classic /9G‑TRONIC automatic transmission) and 725.1… |
| LI35.31-P-080353 | Service bulletin | Sep 14, 2026 | Complaint Whining / humming noises (described as foghorn‑like) from the drivetrain in the rear axle area during cornering. (figure 1) On the… |
| LI27.10-P-075869 | Service bulletin | Sep 14, 2026 | Complaint Only vehicles with a variable transfer case are affected. This can be identified through control unit N45 or N15/7 in the quick te… |
| LI 27.10-P-080851 | Service bulletin | Aug 29, 2026 | Complaint Intermittent shift feel or thud/clunk noise perceived, such as a brief jerk or transmission reaction during certain driving situat… |
| LI27.00-P-075630 | Service bulletin | Aug 5, 2026 | Complaint This document is intended as a pre-case diagnostic reference for transmission related concerns. It will also ensure that if a case… |
| LI27.00-P-080840 | Service bulletin | Aug 4, 2026 | Complaint Mercedes-Benz USA is currently experiencing limited availability of transmission fluid specification ATF 236.17 due to a global su… |
| LI33.30-P-080490 | Service bulletin | Aug 3, 2026 | Complaint Leakage/oil leakage at drive pinion sealing ring (input shaft) (Figures 1-2) Minor leakage/slight seepage at coupling flange nut a… |
| LI35.30-P-058566 | Service bulletin | Jul 14, 2026 | Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The noise is heard once… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Mercedes-Benz, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Mercedes-Benz NCU - 2024120012 a recall?
No. A service campaign 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 NCU - 2024120012 repair free?
A service campaign is usually paid by the manufacturer on the vehicles it names, within the terms and time limit the document sets; the dealer checks the VIN against the manufacturer’s list.
Which vehicles does NCU - 2024120012 cover?
The manufacturer filed it against 1 model year: 2024 Mercedes-Benz GLC-Class. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.