# Service bulletin 34\-079

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: 10161055
- Published by NHTSA: 2019\-06\-10
- Manufacturer's number: 34\-079
- Manufacturer's date: 2019\-05\-21
- NHTSA component: POWER TRAIN

## NHTSA's summary

Fix\-As\-Fail ? Intermittent throttle hesitation may be encountered after installing an optional PTO connector.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2019/MC-10161055-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2019/MC-10161055-9999.pdf)

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

## Components

Transmission and driveline

## Vehicles listed

- 2019 KENWORTH T680
- 2019 KENWORTH T880
- 2019 KENWORTH W990
- 2019 to 2020 PETERBILT 567
- 2019 to 2020 PETERBILT 579

## Recalls for the same vehicles and component

- [20V506000](/recalls/nhtsa/20V506000.md), 2020-08-26: POWER TRAIN:AXLE ASSEMBLY
- [19V911000](/recalls/nhtsa/19V911000.md), 2019-12-19: POWER TRAIN:AXLE ASSEMBLY:AXLE SHAFT; POWER TRAIN:DRIVELINE:DRIVESHAFT
- [2018739](/recalls/tc/2018739.md), 2018-12-24: Powertrain
- [18V931000](/recalls/nhtsa/18V931000.md), 2018-12-21: POWER TRAIN:CLUTCH ASSEMBLY

## Other bulletins for the same vehicles and component

- [26\-035](/bulletins/11035107.md), 2026-07-21, Service bulletin: POWER TRAIN. Updated Eaton's TAIB0885EN Bulletin link.
- [E311](/bulletins/11022496.md), 2025-09-03, Other: ENGINE; POWER TRAIN. Condition, Chassis Affected, and Warranty sections updated with the following verbiage “E311 must be flagged and open in Service Information Record \(SIR\) at the time of RO open date to qualify.” Also, “Through Standard Warranty or any applicable active Extended Warranty” verbiage was removed from Warranty section.
- [T016 / 26\-040](/bulletins/11019217.md), 2025-06-05, Service bulletin: POWER TRAIN. T016: Warranty section updated to include 0.5 hours for test drive. Recommended Repair T016C has been updated from 6.4 hours to 6.9 hours. SRT codes updated in PRWS Claim Coding Table: B25\-17A for 6.9 hours created to replace all other codes. 26\-040: Warranty section updated to include 0.5 hours for test drive. Recommended Repair 26040C has been updated from 6.4 hours to 6.9 hours. SRT codes updated in PRWS Claim Coding Table: B25\-17A for 6.9 hours created to replace all other codes.
- [7\-700](/bulletins/11009757.md), 2024-11-05, Warranty extension: POWER TRAIN; ENGINE. 7/700 Service Agreement \- Letter Only.
- [45\-065](/bulletins/10243360.md), 2023-10-03, Service bulletin: ENGINE AND ENGINE COOLING; POWER TRAIN. Certain 579 MLU chassis equipped with Cummins X15 engines have fan hub bracket hardware that are incorrect for the application and/or under torqued and could become loose and/or fail. Procedures are available to replace and properly torque the hardware.
- [T012](/bulletins/10206097.md), 2022-01-06, Service bulletin: POWER TRAIN. Non\-Safety Campaign: Drivers of vehicles equipped with PACCAR TX\-12 transmissions may experience harsh shifts and gear grinding noise. Premature Main Drive Gear damage may occur due to clutch housing and main case countershaft bearing bore wear.
- [26\-038](/bulletins/10206084.md), 2022-01-06, Service bulletin: POWER TRAIN. Non\-Safety Campaign: Eaton Endurant transmissions may experience premature Main Drive Gear damage due to clutch housing and main case countershaft bearing bore wear. A Clutch Housing Front Cover Kit will be installed to address the issue.
- [21 PBJ](/bulletins/10201946.md), 2021-10-05, Service bulletin: EXTERIOR LIGHTING; POWER TRAIN. Safety Recall – Hill Start Assist \(HSA\) Valve Clearance – NHTSA ID: 21V\-648, TC: 2021\-521. Crossmember mounted Hill Start Assist valve may not have sufficient clearance to the rear axle, resulting in hose or fitting damage. Damage could cause the loss of rear brake signal, resulting in reduced braking capability and increasing the risk of a crash.
- [26\-037](/bulletins/10185190.md), 2021-01-06, Service bulletin: ELECTRICAL SYSTEM:SOFTWARE; POWER TRAIN; EQUIPMENT ADAPTIVE/MOBILITY. Fix\-As\-Fail \- Prior versions of Eaton Endurant transmission software may be prone to setting Linear Clutch Actuator \(LCA\) fault codes leading to possible LCA hardware replacement.
- [26\-035](/bulletins/10185189.md), 2021-01-06, Service bulletin: POWER TRAIN; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT. Non\-safety campaign: Vehicles equipped with an Eaton Endurant 12 speed transmission may experience transmission service lamp activation, no gear engagement from neutral, and/or DTC 511 FMI 7 or 10 is set. Resolution is to update the transmission software and calibrations.

JSON: [/v1/bulletins/10161055](/v1/bulletins/10161055)

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