# Service bulletin 21\-055\-26

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 11035057
- Published by NHTSA: 2026\-07\-18
- Manufacturer's number: 21\-055\-26
- Manufacturer's date: 2026\-07\-09
- NHTSA component: POWER TRAIN

## NHTSA's summary

Flash: 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.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2026/MC-11035057-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2026/MC-11035057-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Transmission and driveline

## Vehicles listed

- 2024 RAM 1500

## Other bulletins for the same vehicles and component

- [S2621000004](/bulletins/11038329.md), 2026-10-07, Service bulletin: POWER TRAIN. The Customer May Complain About a Popping Noise, Grinding Noise, or an Intermittent No Reverse or Forward Transmission Engagement. The Tech May Find Damaged and/or Worn Transmission Output Shaft Splines \(850RE Transmission Only\)
- [S2621000003 REV.A](/bulletins/11030138.md), 2026-03-18, Service bulletin: POWER TRAIN. The vehicle will exhibit a service transmission/check engine warning indicator for the following transmission models: 845RE, 8HP45, 850RE, 8HP50, 8HP70, 8HP75, 8HP75\-PHEV, 8HP75\-LCV, 8HP90, 8HP95. Transmissions may exhibit the following diagnostic codes: P07E4, P1DB2, P0716, P1B14, P0733, P1D90, P1DB7, P1B13.
- [S2621000003](/bulletins/11029770.md), 2026-03-05, Service bulletin: POWER TRAIN. Service transmission/check engine warning indicator for the 850RE, 8HP50, 8HP70, 8HP75, 8HP75\-PHEV transmissions that have fault codes P07E4, P1DB2, P0716, P1B14, P0733, P1D90, P1DB7, P1B13.
- [109011](/bulletins/11026815.md), 2025-12-23, Service bulletin: POWER TRAIN. VALVE BODY \& CONTROL UNIT – TRANSMISSION
- [9100672 Rev 3](/bulletins/11024605.md), 2025-10-29, Service bulletin: POWER TRAIN. Replacement components for transfer case are no longer available. To repair issue, use the following part numbers and follow the I\-sheet instructions for assembly: 68738079AA \- HOUSING 68738084AA \- CAM 68738085AA \- GEAR 68737112AA \- PLATE Please note that the part numbers listed here are transfer case components, not full transfer case part numbers.
- [03\-008\-25](/bulletins/11023321.md), 2025-09-24, Service bulletin: POWER TRAIN. Rear Axle Vibration Shudder Or Chatter Customers may experience the following: ● A chatter, shudder, or vibration from the rear axle during turns. NOTE: This may happen more as the vehicle ages, especially if the vehicle is used extensively for towing or hauling heavy loads. The cause of the concern may be due to degradation of the rear axle fluid. It is very important to follow the routine maintenance schedules on these vehicles when it comes to changing the rear axle fluid if the vehicle is used primarily for towing or hauling heavy loads. If you experience a vehicle with the above condition, please perform the proper maintenance procedures for the rear axle and replace the fluid first before replacing any hardware components. NOTE: This service bulletin is only applicable to vehicles that have no history of an axle fluid replacement. If the vehicle usage includes police, taxi, fleet, off\-road or frequent trailer towing, regular axle fluid changes are required every 3 years or 30,000 miles \(whichever comes first\) per the Maintenance Schedule in the vehicle Owner's Manual. This bulletin involves changing the rear axle lube to possibly address a chatter, shudder or vibration.
- [21\-009\-25 REV. C](/bulletins/11020636.md), 2025-07-09, Service bulletin: POWER TRAIN. 850RE D Clutch Repair Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must have at least 11,265 km \(7,000 mi.\) and exhibit/set one or more of the following Diagnostic Trouble Codes \(DTCs\): ● P0733\-00 \- Gear 3 Shift Incorrect Ratio. ● P1DA8\-00 \- Incorrect Gear Ratio Clutch A B or D Defective. ● P1D92\-00 \- Incorrect Gear Ratio \- Clutch 4 Defective. Customers may also comment on one or more of the following: ● Transmission slips when shifting. ● Vehicle will not move in reverse. ● Vehicle will not shift higher than third gear This bulletin involves replacing the D clutch.
- [9100576](/bulletins/11018658.md), 2025-05-29, Service bulletin: POWER TRAIN. Transfer Case Motor Gear: Confirm the attachment points from the wiring routes when they inspect a shift motor on the t\-case. Review the connection of the connector X238A, make sure it's fully seated and that the lever is fully locked on the connector.
- [9100570](/bulletins/11018453.md), 2025-05-19, Service bulletin: POWER TRAIN. "Transmission Fluid Please note fluid color/condition/odor is NOT an indicator of transmission health and should not be used as the reason for unit replacement. Visible ""glitter"" or debris in the pan does not justify complete unit replacements."
- [9100534 Rev 1](/bulletins/11018452.md), 2025-05-19, Service bulletin: POWER TRAIN. Transmission "Transmission For transmission concerns related to DTCs P0733\-00, P1DA8\-00, and/or P1D92\-00, a repair is available, and transmission replacement is NOT required. Please reference TSB 21\-009\-25 Rev. A, for details on D\-clutch replacement. Please also note, visible ""glitter"" or debris in the pan and fluid color/condition/odor is NOT an indicator of transmission health and should not be used as the reason for unit replacement. Complete unit replacements instead of repairs for these DTCs may be subject to chargeback."

JSON: [/v1/bulletins/11035057](/v1/bulletins/11035057)

[Report an error on this page](https://github.com/wenmar-pro/wenmar-open/issues/new?template=data_correction.yml&title=Data%20correction%3A%20Service%20bulletin%2021-055-26&page=https%3A%2F%2Fopen.wenmarpro.com%2Fbulletins%2F11035057&vehicle=Service%20bulletin%2021-055-26)