A Guide to Transmission Filter Kits for the 2008-2019 Mack GU8
Keep your Mack GU8's transmission shifting smoothly by choosing the right filter kit for your specific gearbox.
- You must identify your specific transmission (e.g., Mack mDRIVE, Allison) before purchasing a filter kit.
- Symptoms of a bad filter include harsh shifting, overheating, and whining noises.
- Aftermarket brands like Wix and ATP offer a reliable, cost-effective alternative to OEM parts.
- Always replace the filter according to your transmission manufacturer's service intervals for your truck's duty cycle.
Identifying Your Mack GU8's Transmission is Critical
Before you can choose a transmission filter kit, you must know which transmission is in your Mack GU8. The filter kit is not one-size-fits-all; it is specific to the make and model of the gearbox. From 2008 to 2019, the GU8 was available with several transmission options, most commonly the automated manual Mack mDRIVE or a fully automatic Allison transmission. You may also find manual Mack Maxitorque transmissions.
Pro Tip: Check the data plate on the side of your transmission housing to identify its manufacturer and model number. This is the only sure way to order the correct filter kit.
Symptoms of a Clogged Transmission Filter
A dirty or clogged transmission filter can starve the system of fluid, leading to serious problems. If you notice any of these signs, it might be time for a transmission service.
- Delayed or Harsh Shifting: Low fluid pressure from a clogged filter can cause the transmission to hesitate or slam into gear.
- Whining or Grinding Noises: A filter that is bypassing fluid or a pump that is struggling for fluid can create unusual noises.
- Overheating Transmission: Restricted fluid flow reduces cooling, causing the transmission to run hot, which can burn the fluid and damage internal parts.
- Slipping Out of Gear: Inconsistent hydraulic pressure can cause the transmission to unexpectedly slip into neutral.
Choosing the Right Aftermarket Filter Kit
For the Mack GU8, you have reliable aftermarket options that offer a good balance of quality and price compared to OEM (Original Equipment Manufacturer) parts. The key is ensuring the kit matches your specific transmission model (e.g., mDRIVE, Allison 3000/4000 series, etc.).
The brands available in our inventory are ATP and Wix.
- Wix: Wix is a widely respected brand in the filtration industry. Forum discussions among automotive enthusiasts often recommend Wix for its consistent quality and reliability. They are generally considered a top-tier aftermarket choice.
- ATP (Automatic Transmission Parts): ATP specializes in transmission components and is known for providing OE-equivalent quality parts. They are a solid choice for a standard replacement to keep your transmission running as intended.
Both brands will provide the necessary filtration to protect your transmission. The most important factor is not necessarily the brand, but the maintenance interval. Never extend the filter change interval beyond the manufacturer's recommendation for your truck's duty cycle.
Estimated Cost Comparison
| Part Type | Price Range |
|---|---|
| New Aftermarket (ATP, Wix) | $12.56 - $132.96 |
| New OEM | $50 - $200+ |
| Shop Labor | $150 - $350 |
Known Issues, TSBs, and Recalls
Searches for recalls and Technical Service Bulletins (TSBs) did not find any specific issues related to the transmission filters on the 2008-2019 Mack GU8. A NHTSA investigation (PE20-005) looked into the mDRIVE transmission's clutch disengagement but did not result in a recall and was not related to the filter's performance. Most transmission issues reported by owners are related to normal wear and tear on heavy-duty components like clutches and gears.
Frequently Asked Questions (FAQ)
How often should I change my Mack GU8's transmission filter?
It depends on your transmission and how you use your truck. Mack recommends service intervals based on duty cycle (Normal, Heavy, Severe). For an mDRIVE, this can range from 250,000 to 500,000 miles. Allison has its own specific schedules. Always follow the manufacturer's guidelines for your specific transmission and application, as neglecting service can lead to costly damage.
Is this a DIY job?
For an experienced mechanic, yes. The job involves draining several gallons of transmission fluid, which can be very messy. You will need to remove a pan or housing, replace the filter(s) and seals, and refill the transmission with the correct type and amount of fluid. If you are not comfortable with this, it's best to have a professional shop do the work.
My kit came with gaskets and seals. Do I need to use them?
Yes. Always use the new gaskets and seals included in the kit. Re-using old, compressed gaskets is a common cause of leaks. Ensure all mating surfaces are perfectly clean before installing the new gasket.
What happens if I install the wrong filter kit?
An incorrect filter will not fit or seal properly. This can cause a massive fluid leak, or it may allow fluid to bypass the filter entirely. This leaves your transmission unprotected from contaminants, which can quickly lead to thousands of dollars in damage. Always verify your transmission model before ordering.
Technical Specifications
OEM Part Numbers: 22038908
Kit contents vary by transmission. May include one or more filters, pan gasket, O-rings, and seals. For example, the Mack mDRIVE kit 22038908 includes the main filter element and housing seals. Allison kits often include an internal sump filter and an external spin-on filter.
We Have This Part in Stock
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.
- Mack GU8: