Transmission Filter Kit Guide for the 2002-2009 Western Star 4900SA
Keep your heavy-hauler's automatic transmission shifting smoothly by choosing the right filter kit.
- This guide is for automatic transmissions only; you must confirm if your 4900SA has an Allison automatic or an Eaton Fuller manual.
- Symptoms of a bad filter include harsh shifting, slipping, and whining noises; service it immediately to prevent damage.
- Both Wix and ATP are reputable aftermarket brands, with Wix often being preferred by professionals for its consistent quality.
- Ensure you buy the correct kit for your transmission's specific pan depth (e.g., 4-inch or 6-inch sump).
Automatic vs. Manual: A Critical First Step
Before buying any parts, the most important step is to identify which transmission is in your 2002-2009 Western Star 4900SA. These trucks were commonly equipped with either Eaton Fuller manual transmissions or Allison automatic transmissions. This guide and the term "Transmission Filter Kit" apply only to models with an Allison automatic transmission.
- Automatic Transmissions (Allison): These use internal filter kits that often include a pan gasket, O-rings, and one or two filters located inside the transmission oil pan.
- Manual Transmissions (Eaton Fuller): These do not use a "kit" in the same way. Service typically involves draining the fluid and cleaning the magnetic drain plugs. Some may have an optional external spin-on filter, which is a separate part.
Pro Tip: Check your truck's original build sheet or look for an identification plate on the side of the transmission housing to confirm the manufacturer (e.g., Allison, Eaton) and model before you shop.
Symptoms of a Clogged Transmission Filter
A dirty or clogged transmission filter restricts fluid flow, which can starve the transmission of the pressure it needs to operate. If you notice any of these symptoms with your automatic, a fluid and filter change should be a top priority.
- Delayed or Harsh Shifting: The transmission may hesitate before going into gear or shift with a noticeable thud.
- Slipping Gears: The engine RPMs may rise without an increase in speed, as if the transmission is not fully engaged.
- Overheating Transmission: Restricted fluid flow leads to poor cooling, causing the transmission to run hotter than normal, which can trigger warning lights.
- Unusual Noises: A whining or buzzing sound from the transmission area can indicate the pump is struggling to pull fluid through a clogged filter.
Choosing the Right Aftermarket Filter Kit
For a critical component like the transmission, filter quality matters. Sticking with reputable aftermarket brands is a safe bet. The two main brands available are Wix and ATP, both of which offer kits for Allison transmissions.
Brand Quality: Wix vs. ATP
Wix: Wix is a highly respected name in the filter industry, for both heavy-duty and light-duty vehicles. Their products are widely considered to be OEM-quality or better. Forum discussions often show a preference for Wix when given the choice, due to its established reputation for quality and reliability. Many professional mechanics trust Wix for transmission service.
ATP (Automatic Transmission Parts): ATP specializes in transmission components and is a well-known aftermarket supplier. They offer a wide range of kits and are generally seen as a reliable standard replacement option. Some users appreciate their unique gasket designs, which can help with installation. While considered a solid choice, some experienced users may lean towards Wix if available.
Important: Allison automatic transmissions in this chassis can have different oil pan depths (e.g., 4-inch or 6-inch sumps). These require different filter kits. Always verify your pan depth to ensure you purchase the correct kit.
Known Issues, Recalls, and TSBs
Searches for official recalls and technical service bulletins (TSBs) from the National Highway Traffic Safety Administration (NHTSA) did not find any issues directly related to the transmission filter kits for the 2002-2009 Western Star 4900SA. Recalls found for the 4900 series were related to other systems like steering and electrical components.
Cost of Replacing a Transmission Filter Kit (2002-2009 Western Star 4900SA)
| Part/Service | Estimated Cost |
|---|---|
| New OEM (Allison) Filter Kit | $45 - $75 |
| New Aftermarket (Wix, ATP) Filter Kit | $13 - $133 |
| Shop Labor | $150 - $300 |
| Total Professional Replacement (Aftermarket) | $163 - $433 |
Frequently Asked Questions (FAQ)
How often should I change the transmission filter on my 4900SA?
For heavy-duty applications, it's best practice to change the transmission fluid and filter(s) at the intervals recommended by the transmission manufacturer (Allison). If you don't have the manual, a general guideline is every 25,000 to 50,000 miles, depending on your hauling load and operating conditions (e.g., city vs. highway). Always change the filter when you change the fluid.
What is included in a typical aftermarket transmission filter kit?
For an Allison automatic, a kit usually contains the necessary internal filters (often two), a new pan gasket, and any required O-rings for a complete service.
Can I just change the fluid and not the filter?
This is not recommended. The old, dirty filter can contaminate your new fluid and will continue to restrict flow, defeating the purpose of the service. The filter is designed to be replaced with the fluid to ensure the transmission stays clean.
Is a special fluid required for my transmission?
Yes. Allison automatic transmissions require a specific type of fluid that meets their specifications (e.g., TES-295, TES-668). Using the wrong fluid can cause shifting problems and damage the transmission. Always consult your owner's manual or the transmission manufacturer's recommendation.
Technical Specifications
OEM Part Numbers: 29548987 29540493 29545776 29548988 29540494
Kits are specific to Allison 3000 & 4000 series automatic transmissions. Key variations depend on the transmission's oil sump depth, typically 2-inch, 4-inch, or 6-inch. Kits include internal filters, gaskets, and O-rings.
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- Western Star 4900SA:
- 🛍️ Shop This Part
- Automatic vs. Manual: A Critical First Step
- Symptoms of a Clogged Transmission Filter
- Choosing the Right Aftermarket Filter Kit
- Known Issues, Recalls, and TSBs
- Cost of Replacing a Transmission Filter Kit (2002-2009 Western Star 4900SA)
- Frequently Asked Questions (FAQ)
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