# Service bulletin 21\-006\-21

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: 10188816
- Published by NHTSA: 2021\-03\-15
- Manufacturer's number: 21\-006\-21
- Manufacturer's date: 2021\-02\-13
- NHTSA component: POWER TRAIN

## NHTSA's summary

Flash: Transmission Control Module \(TCM\) Updates This bulletin involves reprogramming the TCM with the latest available software. The customer may experience one or more of the following:Poor shift quality. Shift or gear hunting. The 6\-4 and 5\-3 shift may have a bump. Some 2\-3, 3\-4 and 4\-5 shifts may "flare" when cold. Coastdown bump. The following software enhancement is also available: Stored faults can only be cleared by a diagnostic scan tool, this software will allow the TCM to self clear.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2021/MC-10188816-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2021/MC-10188816-9999.pdf)

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

## Components

Transmission and driveline

## Vehicles listed

- 2019 RAM 3500
- 2019 RAM 4500

## Recalls for the same vehicles and component

- [2020025](/recalls/tc/2020025.md), 2020-01-24: Powertrain
- [20V043000](/recalls/nhtsa/20V043000.md), 2020-01-24: POWER TRAIN:AUTOMATIC TRANSMISSION

## Other bulletins for the same vehicles and component

- [21\-039\-26](/bulletins/11032827.md), 2026-05-20, Service bulletin: POWER TRAIN. Replace K1 Clutch / Input Shaft Assembly Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must exhibit/set the following Diagnostic Trouble Code \(DTC\): ● P0731\-00 \- Gear 1 Shift Incorrect Ratio \(This DTC will set during a key cycle and shifting into Drive\). Customers must also comment on the following: ● The transmission will not shift into or out of 1st \- 4th gears. 5th and reverse gears are still available This bulletin involves replacing the K1 clutch and possibly the K1 input shaft drum sub\-assembly. These repairs are to be performed only if the vehicle is inoperable due to K1 clutch failure
- [21\-039\-26](/bulletins/11032650.md), 2026-05-13, Service bulletin: POWER TRAIN. Replace K1 Clutch / Input Shaft Assembly Customers must experience a Malfunction Indicator Lamp \(MIL\) illumination and the vehicle must exhibit/set the following Diagnostic Trouble Code \(DTC\): ● P0731\-00 \- Gear 1 Shift Incorrect Ratio \(This DTC will set during a key cycle and shifting into Drive\). Customers must also comment on the following: ● The transmission will not shift into or out of 1st \- 4th gears. 5th and reverse gears are still available This bulletin involves replacing the K1 clutch and possibly the K1 input shaft drum sub\-assembly. These repairs are to be performed only if the vehicle is inoperable due to K1 clutch failure
- [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.
- [S2516000001](/bulletins/11024577.md), 2025-10-29, Service bulletin: POWER TRAIN. Driveline Vibration. Prop Shaft Diagnostic Information.
- [9100642](/bulletins/11021844.md), 2025-08-13, Service bulletin: POWER TRAIN. When customer complaint is related to inoperative 4 Wheel Drive shifter, loss of 4WD function and/or 4WD related MIL please reference SOL Case \#S2508000062 prior to replacement of Transfer Case shift motor.
- [03\-001\-25 REV. A](/bulletins/11014369.md), 2025-02-19, Service bulletin: POWER TRAIN; UNKNOWN OR OTHER. "Clicking Noise While In 4WD Customers may experience the following: ● Ratcheting, click, or clicking noise in 4WD while turning. This bulletin involves replacing the front driveshaft."
- [03\-001\-25](/bulletins/11014157.md), 2025-02-11, Service bulletin: POWER TRAIN. "Clicking Noise While In 4WD ustomers may experience the following: ● Ratcheting, click, or clicking noise in 4WD while turning. his bulletin involves replacing the front driveshaft"
- [9100393 Rev 1](/bulletins/11013489.md), 2025-02-03, Service bulletin: POWER TRAIN. TRANSFER CASE BW 44\-46 If fluid leak is present between the transfer case and the rear driveshaft on a 4WD vehicle the Output Shaft Seal should be considered in lieu of entire transfer case or driveshaft replacement. In the case of major damage to components, contact StarCenter and/or proceed with replacements as necessary.
- [102307](/bulletins/11012351.md), 2025-01-06, Service bulletin: POWER TRAIN. GEAR \- REACTION SUN
- [102387](/bulletins/11012318.md), 2025-01-04, Service bulletin: POWER TRAIN. SEAL \- OUTPUT SHAFT

JSON: [/v1/bulletins/10188816](/v1/bulletins/10188816)

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