Why Your Transmission’s Hidden Filter Needs More Attention Than You Think
Modern automatic transmissions are marvels of engineering, but many drivers don’t realize that their transmission contains a critical component working behind the scenes: an internal filter. Unlike the easily accessible external filters of older vehicles, these internal filters require special attention and professional service to maintain your transmission’s health and longevity.
Understanding Internal vs. External Transmission Filters
Depending on the positioning, all automatic transmission filters can be divided into internal and external filters. External filters are located on the transmission housing, and in most cases, they are attached to the housing by means of a thread joint. This type of filters can be found on old automatics. These filters can be found on many modern automatic transmissions. Internal filters have larger filtration areas than their external analogs and they have significantly increased resource. On average, the internal filter has the replacement cycle of approximately 60-70 thousand kilometers.
The automatic transmission filter sits between the transmission pan and the tube that draws transmission fluid into the transmission pump. Most look like a metal plate with a mesh-like insert, and it helps prevents contaminants from getting into the transmission and causing damage. Automatic transmissions have internal filters designed to capture only large particles. These filters are designed as a pickup to keep large particles from flowing through the transmission. These filters are on the suction side of the pump.
The Challenge of “Sealed for Life” Transmissions
Many modern vehicles come with what manufacturers call “sealed for life” or “lifetime” transmissions, which can be misleading for consumers. The statements “Lifetime, Lifetime Fill, Fill for Life, or Sealed for Life” used by vehicle and transmission manufacturers, is typically understood to indicate the transmission fluid and transmission filter will last the lifetime of the vehicle while under warranty. However, from our 30 years of hands-on automotive experience, there is no such thing as a truly “sealed for life” or “lifetime transmission fluid.” Over time, all transmission fluids will eventually deteriorate, break down, and become contaminated and will need to be changed.
The dirty little secret is that “filled-for-life” really means “filled for the life of the warranty.” This creates a significant challenge for vehicle owners who plan to keep their cars beyond the warranty period.
Why Internal Filter Service Matters
The transmission filter helps to remove dirt and contaminants from the automatic transmission fluid, which serves several purposes, such as: Cleaning, cooling, lubricating, and protecting the transmission … A clogged or ill-fitting filter can lead to leaking, noise, contamination, and — worst case scenario — transmission failure.
Internal gear wear can sometimes result in metal shavings floating around in the transmission fluid as your vehicle gets older. In order to keep things shifting smoothly, the transmission filter sifts out the metal and keeps it from causing problems. Because many gearboxes aren’t completely sealed — there are breather vents, a filler tube and a level check tube — sometimes dirt and other foreign particles can find their way inside the fluid as well, where they are also cleaned out by the filter.
Signs Your Internal Filter Needs Service
Since internal filters are hidden from view, recognizing the warning signs becomes crucial. The first is if your transmission fluid starts to smell burnt, or if it turns a dark color. These are indications that it’s no longer as effective as it could be and should be changed — the filter needs to go too, as it has probably soaked up a lot of the old fluid over the course of its lifespan.
Another indication is if you start to experience unusual transmission behavior, either in the form of clunky gearshifts or unusual noises. These can also be clues that the filter and fluid need to be replaced. Weird burning smell due to an overheated transmission: When the filter restricts fluid flow, internal transmission components receive less lubrication, increasing friction and heat. This can overheat the transmission, resulting in a burnt smell from the fluid or scorched internal parts.
The Service Challenge
However, internal filters are more expensive than externals and it is much more difficult to replace internal filters, as you’ll have to remove the transmission pan first to reach the internal filter (it will also be necessary to replace the pan gasket). Because many transmission pans don’t have drain plugs, changing the fluid can be a messy proposition –the entire pan must be removed. But even on vehicles that do have drain plugs, the pan still must be removed to change the filter.
This complexity is why professional service becomes essential. While it is possible for those with proper tools and mechanical ability to replace a filter, having the proper facilities to lift the vehicle and the complexity involved in replacement, it is often best to leave things to a transmission repair specialist to properly replace your transmission filter.
Professional Service in Athens, Georgia
For Athens area residents dealing with internal transmission filter concerns, Pro Transmissions offers expert service with a deep understanding of modern transmission systems. With a team of seven skilled technicians, including two Master Certified Technicians, we bring decades of combined experience to every job. Our commitment to quality is backed by industry-leading warranties on all our transmission rebuilds and general repairs.
At Pro Transmissions, we are more than just a transmission shop. We are your neighbors, committed to keeping Clarke County moving. Our team values honesty, integrity, and exceptional service. Whether you need a comprehensive transmission flush athens service or internal filter replacement, their family-owned business brings the expertise needed for today’s complex transmission systems.
Recommended Service Intervals
Despite manufacturer claims of “lifetime” service, experts recommend more frequent maintenance. In automatic transmissions/transaxles, the recommended service interval is about every 30,000 miles or 30 months. Even with advancements in fluid chemistry, your “lifetime” transmission fluid should now be getting replaced closer to 30,000 or 40,000 miles, not the “lifetime” claimed in your owner’s manual.
Things like towing, mountain driving, etc. will increase the stress on your transmission and require more frequent servicing. For vehicles operating in demanding conditions, more frequent internal filter service becomes even more critical.
The Bottom Line
Regular fluid and filter changes can prevent many issues with the internal transmission components. Do not wait to change the transmission fluid and filter until after the transmission gives you signs of problems. While internal filters may be hidden from view and more challenging to service, they play a crucial role in transmission longevity.
Paying a couple of hundred dollars for a fluid service is much better than having to either pay thousands of dollars for a transmission repair or tens of thousands of dollars for a new vehicle! Don’t let the “sealed for life” marketing fool you – your transmission’s internal filter needs attention to keep your vehicle running smoothly for years to come.