Ram bulletin 21-055-26
What it saysFlash: Transmission Control Module (TCM) Updates Customers may comment on one or more of the following: SYMPTOM: Harsh or slipping feeling during upshifts (1st - 5th). NHTSA’s full summary ↓
Ram filed this with NHTSA as a service bulletin dated Jul 9, 2026, received Jul 18, 2026, about the power train. It names 1 model year (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.
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What the bulletin says
Source: NHTSA's summary of the manufacturer's communicationFlash: Transmission Control Module (TCM) Updates Customers may comment on one or more of the following: SYMPTOM: ● Harsh or slipping feeling during upshifts (1st - 5th). ● Harsh or slipping feeling during kickdown events under throttle. ● Transmission fluid odor (burnt smell). This bulletin involves reprogramming the TCM with the latest available software.
Document filed under this number
| Document | Kind | Dated | NHTSA id | At NHTSA |
|---|---|---|---|---|
| 21-055-26 | Service bulletin | Jul 9, 2026 | 11035057 |
What the document itself lists
Labour operation and the time the manufacturer allows
| Operation | Description | Time |
|---|---|---|
| 18-19-05-TR | Module, Transmission Control (TCM) - Reprogram | 0.2 hrs |
Read by machine from the document NHTSA serves (2 pages), read Sep 29, 2026. A part number is shown only where it matches Ram’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 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 74 complaints with NHTSA since 2015. 14 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.
Came to a stop sign, waited for traffic to clear to turn left as I floored it started moving and then all of a sudden loss acceleration and notice rpm ramped up to 7k. As in was just coasting I notice only my rpm would go up but the truck wouldn’t move. Lucky I coasted to the side of road and shifted to park.
2024 Ram 1500 · Power Train · filed with NHTSA Aug 2, 2024
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 group70 other manufacturer communications filed against the Ram 1500 under the same component group (power train), newest first. The eight newest are listed; the rest are on the Ram list.
| Number | Kind | Dated | NHTSA’s summary |
|---|---|---|---|
| 21-062-26 | Service bulletin | Sep 25, 2026 | Transmission Rattle Customers may comment on the following: SYMPTOM: ● Rattle noise coming from the transmission. This bulletin involves ins… |
| 18-071-26 | Service bulletin | Jul 22, 2026 | Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle mus… |
| 21-057-26 | Service bulletin | Jul 9, 2026 | Flash: Transmission Control Module (TCM) Updates Customers may comment on one or more of the following: SYMPTOM: ● Harsh or slipping feeling… |
| 21-056-26 | Service bulletin | Jul 9, 2026 | Flash: Transmission Control Module (TCM) Updates Customers may comment on one or more of the following: SYMPTOM: ● **Harsh or slipping feeli… |
| 21-054-26 | Service bulletin | Jul 9, 2026 | Flash: Transmission Control Module (TCM) Updates Customers may comment on one or more of the following: SYMPTOM: ● Harsh or slipping feeling… |
| 112748 | Service bulletin | Jun 11, 2026 | SHIFTER - TRANSMISSION |
| 112747 | Service bulletin | Jun 11, 2026 | SHIFTER - TRANSMISSION |
| 18-059-26 | Service bulletin | Jun 6, 2026 | Flash: Powertrain Control Module (PCM) Updates Customers must experience a Malfunction Indicator Lamp (MIL) illumination and the vehicle mus… |
Quote the number at the service desk. It is what the dealer’s system is keyed on.
Every manufacturer communication NHTSA holds for Ram, by the number printed on the letter.
Common questions
Source: NHTSA, 49 CFR 579.5Is Ram 21-055-26 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 21-055-26 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.
Which vehicles does 21-055-26 cover?
The manufacturer filed it against 1 model year: 2024 Ram 1500. Whether one particular vehicle is affected is a matter of its VIN and its build, not its model year alone.