1/28/26, 2:38 PM Bulletin - X

FSO15: PACCAR TX-12 MTM Loose Rail Cap Screws

11/10/2025 7 Edit (© Clone

FSO15
PACCAR TX-12 MTM Loose Rail Cap Screws

Section

Transmission - 26

Subject
PACCAR TX-12 MTM Loose Rail Cap Screws

Revision

01/28/2026: The chassis list was updated to indicate T680 or T680 Next Gen. SRT codes B25-28A and
B25-28B apply to T680 Next Gen chassis.

Condition

Certain chassis equipped with a PACCAR TX-12 transmission have Mechatronic Transmission Module
(MTM) rail cylinder cap screws that could become loose. This may cause the transmission not to shift
and the transmission service lamp to illuminate.

The repair procedure is now available.

Chassis Affected

350 US vehicle model year 2022-2023 T680 / T680 Next Gen manufactured between 05/10/2021 and
06/29/2022 equipped with a PACCAR TX-12 transmission that has an MTM serial number in which the
five bolded digits are sequentially less than 22342 (12S22342145012).

Action

Campaign

Service all affected chassis that enter your dealership, even if the customer has no issue with the
chassis.

1. In Service Management, select campaign FS015 to add it to the case. If the unit is released back
into service without performing the repair, make sure to also release the campaign in Service

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1/28/26, 2:38 PM Bulletin - X
Management.

2. If you are not using Service Management to start repair orders, review SIR for “Complete” next to
the FS015 campaign code prior to performing this repair.

3. Refer to the Procedure and Links sections for detailed instructions on this repair.

Warranty

Starting on 11/10/2025 and through standard PACCAR TX-12 warranty coverage of 5 years / 750,000
miles (excludes extended warranty), repairs must be completed before campaign expiration of
12/01/2026. Kenworth will pay for parts at dealer net plus applicable mark-up and labor.

[| | NOTE

If the Mechatronic
Transmission Module has an
Eaton/Cummins Joint Venture
(ECJV) label, the repair has
already been completed.
Repairs should not be
performed on a transmission
that has the ECJV label.

If the Warranty Return Center
receives an MTM with an
ECJV label under this
campaign, it will be denied.

wn) ETM |
otis Br! PA-10000715R

. es VKA

ere $12518003162386 2

¢ 0.1 hours labor for inspecting the MTM label and finding that it is an ECJV label or the five bolded
digits of the serial number are 22342 or sequentially higher (12S22342145012) and no repairs are

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1/28/26, 2:38 PM

Bulletin - X

required. Use Recommended Repair Code FS015A.

e 6.2 hours labor for generating a Service Activity Report, R&l Transmission, R&l MTM, perform
MTM Rail Service Procedure, and perform road test. Use Recommended Repair Code FS015B.

e If any fault code diagnostics are required, they must be filed as a supplemental claim.

e File an additional claim for extraordinary circumstances. A recommended repair for standard labor

must be filed first.

e File the claim within 14 days in accordance with the warranty policy.

e Kenworth dealers may perform FS015 repairs on a Peterbilt chassis, but Recommended Repair
Codes do not apply. For Peterbilt chassis repairs, use a long form claim and enter FS015 in the

Campaign Code field.

Take-Off Parts Disposition: Destroy take-off parts 30 days after claim is paid.

PRWS CLAIM CODING

Campaign

Campaign

Code: FS015 Type: Field Repair

Claim PACCAR . ;

Category: |Transmission Repair Type: |Proactive

Customer

Concern |062 Causal Code: |62

Code:

Corrective vs ags

Action 32 Responsibility CampSupp

Code:

Code:

Failure |996-015-105 |Causal Part: |E74-1020

Location:

Supplier |21888AA SRT Code: B25-28A

Code: 0.1 hours
Inspect the
MTM label
per the
bulletin
procedure.
B25- 28B
6.2 hours
Generate a
Service
Activity
Report, R&l
Transmission,
R&l MTM,
perform MTM
Rail Service

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1/28/26, 2:38 PM Bulletin - X

Procedure,
and perform
road test.

Parts
Parts are available from PACCAR Parts.

. Part os
Quantity Number Description
Sour Parts Cleaner -
60mL | °°" ILoctite SF 7063
Locally ;
(or equivalent)
MTM O-ring Kit
Includes:
¢ Loctite
Anaeraobic
1 E74- Sealer
1020 5188
¢ Loctite
Thread
Locker
71232
As E22- |Transmission Oil
Needed} 1020 |Drain/Fill Plug

Procedure

Please follow your dealership's safety procedures and precautions to ensure the vehicle can be
safely repaired and maintained.

A WARNING

Read, understand, and follow
each statement regarding cap
screw installation and torque
specification requirements.
Failure to install and torque
cap screws to specification
may result in major vehicle
component damage, severe
injury, or death.

1. Inspect the Mechatronic Transmission Module (MTM) label for type and serial number:

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1/28/26, 2:38 PM Bulletin - X

EATON E:-In GS

A-1000071S R-A 1 io acai .

VIKA VERA

S: 12820051163732 4—2 812518093 162836 ROT}?
MTM Label Location

° If itis an Eaton/Cummins Joint Venture label (pictured below) or the five bolded digits of the
MTM serial number are 22342 or sequentially higher (12522342145012), then no repairs are
required. File a claim for inspecting the MTM label.

a ETN &

Al pa-10000715R 1
i

Eaton/Cummins Joint Venture Label

° If it is an Eaton label (pictured below) and the five bolded digits of the MTM serial number are
sequentially lower than 22342 (12522342145012), then proceed to step 2.

EATON

A-VOOQ0TTS RA 1
Vv KA

S: 1200S 110IT I? i

Eaton Label
2. Create an Eaton Service Activity Report.
3. Refer to the Eaton TRSM0950 procedures in the Links section below.

Perform all of the following procedures:

© Transmission R&l Procedure.
© Mechatronic Transmission Module R&l Procedure.
© MTM Rail B C and D Cylinder Procedure.

= Disregard Special Instructions that state “Perform this entire procedure only if guided
here by MTM Rail B, C, and D Cylinder Inspection Procedure.” — This is a proactive

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1/28/26, 2:38 PM Bulletin - X

repair procedure and is not dependent on inspection results.

= Unless applicable fault codes are present, do not proceed past step 22 in the
“Assemble Rail C and D” section of the procedure.

4. Fault code diagnostics are not covered under this bulletin unless the fault codes are specifically
called out in TAIB-0994.

5. Once all applicable procedural steps in TRSM0950 are completed, perform a road test to verify the
repair.

Attachments

TRSMO0950: Transmission R&l Procedure
TRSMO950: Mechatronic Transmission Module R&l Procedure
TRSM: MIM Rail B C and D Cylinder Procedure

Only reference TAIB 0994 to determine if applicable fault codes are present.
Eaton TAIB 0994

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