A Guide to the Transmission Filter Kit for the 2007-2008 Workhorse R26
Keep your Allison transmission shifting smoothly by understanding its unique dual-filter system and choosing the right parts.
- The Allison transmission in your R26 has two filters: an easy-to-change external spin-on filter and an internal pan filter.
- When changing the external filter, you must clean and transfer the reusable magnet from the old filter to the new one.
- For this heavy-duty application, use a high-quality filter from a brand like Wix or genuine Allison parts to ensure reliability.
- Always use a full synthetic transmission fluid that meets Allison TES-295 or TES-668 specifications.
Understanding Your R26's Dual-Filter Transmission
The Allison transmission in your Workhorse R26 uses two separate filters to keep the fluid clean, and a service kit may include one or both. Knowing the difference is key to ordering the right parts.
- External Spin-On Filter: This filter looks like a standard engine oil filter and is mounted on the outside of the transmission. It is designed for fine particle filtration and is the most frequently changed filter.
- Internal Sump Filter: This filter is located inside the transmission oil pan. It is a larger, flatter filter designed to catch bigger debris. Replacing it requires draining the fluid and removing the transmission pan.
Don't Throw Away the Magnet! When you replace the external spin-on filter, you will find a round, flat magnet on top of it. This magnet traps fine metallic particles. It is reusable and MUST be cleaned and transferred to the top of your new filter before installation. Many new filters do not include a new magnet.
Symptoms of a Clogged Transmission Filter
When filters become clogged, fluid flow is restricted, starving the transmission of the clean fluid it needs to cool and lubricate itself. This can lead to serious and expensive damage. Watch for these warning signs:
- Harsh or Delayed Shifting: If gear changes become rough, or if there's a long pause before the transmission engages, it could be due to dirty fluid affecting hydraulic pressure.
- Transmission Overheating: A clogged filter is a common cause of overheating, as it restricts the flow of fluid that cools the transmission. This is especially dangerous on a heavy vehicle like an R26.
- Whining or Grinding Noises: Strange noises often indicate that internal parts are not being properly lubricated due to restricted fluid flow.
Choosing the Right Aftermarket Filter Kit
The Allison transmission is a robust and expensive piece of machinery. While aftermarket parts can offer significant savings, quality is critical. For this application, filters are generally available from several brands with different reputations.
Brand Quality Tiers
- Higher-Tier Aftermarket (Wix): Wix is a well-regarded brand known for making high-quality filters that meet or exceed OEM specifications. Many mechanics and experienced owners trust Wix for its reliable construction and filtration performance, making it a solid alternative to genuine Allison parts. The Wix 57701 is a common cross-reference for the Allison external spin-on filter.
- Standard Aftermarket (ATP): ATP is a popular aftermarket brand often praised for its innovative "Third Hand" pan gaskets. These gaskets have undersized holes that grip the pan bolts, making it easier to align and install the pan without the gasket slipping. While most users report good experiences, there have been occasional complaints about gaskets being damaged from being folded in the box.
- Value-Oriented (Premium Guard): Premium Guard offers a budget-friendly option for transmission service. They provide complete kits that are functional and widely available. For a heavy-duty application like the R26, some owners may prefer to use a higher-tier filter, but Premium Guard remains a viable choice for those on a tighter budget.
OEM vs. Aftermarket: For a critical and expensive component like an Allison transmission, using genuine Allison parts is always the safest bet. They are designed specifically for the transmission and guarantee correct fit and performance. However, a high-quality aftermarket filter from a reputable brand like Wix is a dependable and cost-effective alternative. Avoid unbranded, low-cost filters, as failure could lead to a catastrophic transmission failure.
Estimated Cost of Transmission Filter Kits (2007-2008 Workhorse R26)
| Part Type | Price Range |
|---|---|
| New Aftermarket Kit (ATP, Premium Guard, Wix) | $38.13 - $130.49 |
| New OEM (Genuine Allison) | $120 - $250+ |
| Shop Labor | $100 - $250 |
Note: Prices are estimates and can vary based on kit contents (spin-on only vs. complete kit), supplier, and location. Labor costs vary by shop.
Frequently Asked Questions (FAQ)
How often should I change the transmission filters on my R26?
For a heavy vehicle like a motorhome, it is best to follow a severe service schedule. Allison generally recommends changing the external spin-on filter every 12 months or 12,000 miles. The internal filter and a full fluid change are typically recommended every 30,000 to 50,000 miles. Always consult your Workhorse or Allison service manual for the exact intervals for your vehicle.
Do I have to change both filters at the same time?
No. The external spin-on filter is designed to be changed more frequently than the internal sump filter. Many owners change the external filter with every other engine oil change to keep the fluid as clean as possible, while only changing the internal filter during a full pan-drop service.
What kind of transmission fluid does the Workhorse R26 use?
You must use a full-synthetic transmission fluid that meets Allison's specifications. Look for a fluid that is TES-295 or the newer TES-668 approved. Using the wrong fluid can cause shifting problems and damage the transmission.
Are there any recalls I should know about?
Searches did not find any transmission-specific recalls for the 2007-2008 R26 chassis. However, owners should be aware that other Workhorse chassis from this era were subject to a major recall for sticking brake calipers and a fuel rail clip recall. It is always a good idea to check for any open recalls on your specific vehicle's VIN with the NHTSA.
Technical Specifications
OEM Part Numbers: 29539579 29537268
Fits Allison 1000, 2000, 2100MH, 3000, and 4000 series transmissions. Kit may contain an external spin-on filter, an internal sump filter, and a pan gasket.
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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.
- Workhorse Custom Chassis R26: