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Service bulletins for the 2020 Western Star 4900

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.

156 on file from NHTSA, as of 2026-10-19.

By type

By component

Bulletins, newest first
17TS-12REV2020-01-03. Service bulletin. ELECTRICAL SYSTEM:WIRING; ENGINE AND ENGINE COOLING; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT. Technical Service Letter for GHG17 Heavy Duty Engine Platform 1-BOX Aftertreatment System (ATS) Wire Harness experiencing chaffing caused by vibration and dirt collecting in the harness conduit.
WI19-0222020-01-02. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT; ELECTRICAL SYSTEM. Warranty Information Letter announcing Detroit NOx Sensor Circuit Improvements for GHG17 After Treatment Systems
SBW72-0082019-12-20. Service bulletin. STRUCTURE; VISIBILITY. Service Bulletin for Window Regulator Retrofit.
SBW41-0022019-12-20. Service bulletin. POWER TRAIN. Service Bulletin for Midship Bearing Replacement for built vehicles with driveshafts SPL140, SPL170 or SPL250 with first order driveline vibration.
SS10345772019-12-03. Service bulletin. EQUIPMENT; POWER TRAIN; STRUCTURE; EQUIPMENT ADAPTIVE/MOBILITY. Service Solution to address WST Cab drone / vibration / tapping Under acceleration for vehicles w/Eaton Manual Trans.
SS10345792019-12-03. Service bulletin. EQUIPMENT; EQUIPMENT ADAPTIVE/MOBILITY. Service Solution for prematurely failing coolers on WST Models equipped with Allison Transmissions and Rocore Transmission coolers (07-23256-001) with tow pin front X-member. Part number 07-25266-000 is a direct replacement of the failing coolers and requires no modifications or plumbing changes.
CAL WST 32-0022019-12-02. Service bulletin. EQUIPMENT; SUSPENSION; EQUIPMENT ADAPTIVE/MOBILITY. Customer Advisory Letter for Airliner welded axle seats. The welded axle seats were installed incorrectly on the rear most drive axle for specific vehicles resulting in an incorrect axle pinion angle. The existing welded axle seats will be removed and replaced with new axle seats installed in the correct orientation.
SBW00-0042019-11-24. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. Service Bulletin explaining Western Star's courtesy engineering policy.
CALWS15-0012019-11-21. Service bulletin. POWER TRAIN; EQUIPMENT ADAPTIVE/MOBILITY; ENGINE. Customer Advisory Letter for Allison flex plate mounting bolts. The incorrect flex plate mounting bolts were installed for certain vehicles.
SBW41-0022019-11-21. Service bulletin. SUSPENSION; EQUIPMENT ADAPTIVE/MOBILITY; EQUIPMENT. Service Bulletin for midship bearing replacement. This procedure applies to all vehicles built with driveshafts SPL140, SPL170 or SPL250 with first order driveline vibration.
SB98-0152019-11-20. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL; EQUIPMENT ADAPTIVE/MOBILITY. Service Bulletin for paint finish standards. Delfleet One has been added for aftermarket use. This version replaces service bulletin dated May 5, 2017.
WP19-0192019-11-20. Service bulletin. EQUIPMENT:OTHER:OWNERS/SERVICE/OTHER MANUAL. Warranty Policy letter announcing service locations have 90 calendar days from delivery to open a repair order which Identifies and addresses discrepancies from the sales order.
19-018WI2019-10-31. Service bulletin. EQUIPMENT. WARRANTY INFORMATION LETTER for coverage validation
SS10344992019-10-30. Service bulletin. EQUIPMENT; ELECTRICAL SYSTEM. Service Solution on failing RX modules in Western Star vehicles.
SS10345312019-10-30. Service bulletin. SERVICE BRAKES, AIR; EQUIPMENT. Service Solution for WABCO HP air dryer turbo cut-off valve replacement.
SBW98-12019-10-30. Service bulletin. STRUCTURE. Service bulletin updating the Important Information section and adding instructions for proper visual inspection distance for paint finish standards.
19-016WP2019-10-30. Service bulletin. EQUIPMENT. WARRANTY POLICY LETTER- Hold disposition for Parts has been eliminated
19-015WP2019-10-29. Service bulletin. EQUIPMENT. Warranty Policy Letter- To assist customers and the service network regarding the Aftermarket Parts Limited Parts Warranty (Parts Warranty).
19TS-4REV2019-10-28. Service bulletin. ENGINE AND ENGINE COOLING. Technical Service Letter Revision on heavy duty coolant oil module and oil filter change. Older modules will not be compatible with newer module.
19TL-202019-10-26. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. Tool Letter for DAVCO Shop Pro FXP 95-230V compatible for Australia Electrical Systems.
19TL-192019-10-26. Service bulletin. ELECTRICAL SYSTEM; EQUIPMENT. Tool Letter for DAVCO Shop Pro FXP 95-230V compatible for Chile and Italy Electrical Systems
19CSA-162019-10-26. Service bulletin. ENGINE AND ENGINE COOLING. Customer Service Announcement that eParts is being retired and that PartsPro should be used instead for Detroit Engine Parts Information.
17TS92019-10-25. Service bulletin. ENGINE AND ENGINE COOLING. Technical Service Letter communicating that information on DD Heavy Duty Platform Belt and Belt Tensioner can be found on TechLit.
P&SSep20192019-10-08. Service bulletin. EQUIPMENT. Parts and Service Committee meeting minutes
DOC-10345002019-10-03. Service bulletin. ENGINE AND ENGINE COOLING; EQUIPMENT:APPLIANCE:AIR CONDITIONER. Service Solution to fix AC cooling performance due to improper HVAC function.

The summaries are NHTSA's. Each bulletin's page links NHTSA's copy of the manufacturer's document.