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What to Know About Servicing Your Transmission Fluid


At Honest Wrenches, we strive to educate rather than just sell to our clients, so that we can make the best-informed decision to suit their needs and timeline of their vehicle. We find that transmission fluid service is a subject that our customers have questions on. So, do you need to service your transmission fluid? The short answer is yes.


The myth that if you service your transmission fluid, your transmission will go out, is absolutely false. The job of transmission fluid is to clean, cool, and lubricate the internal components of your transmission. This means that over time, the transmission fluid will lose its lubricity, as well as the ability to clean and cool the transmission so you’ll need to service it so that your system will work properly. This is especially true during the summer months when it’s so hot out, as your transmission fluid will further degrade at high temperatures.


When servicing, flushing, or changing your transmission fluid it is extremely important that it is done correctly. This is where the myth of the transmission fluid service being dangerous for your transmission comes from, because if it is done incorrectly, it can be. If you do a drain and fill on your transmission fluid you can only get about 30% of the capacity of the fluid out. If you have it serviced, or flushed with an effective machine, it will get 99% of the old fluid out while replacing it with clean new fluid. 


If I had ½ gallon of spoiled milk, and were to mix it with another ½ gallon of good milk, I’d end up with a gallon of spoiled milk. That is exactly what happens with transmission fluid if you do not service it correctly. Like topping off your spoiled milk with fresh milk, adding new transmission fluid to old transmission fluid will just taint what’s good. Transmission fluid cleans, cools, and lubricates the internal components of your transmission, so you want to make sure that you’re keeping up on its maintenance.


If you don’t clean out all of the old “spoiled” fluid that captured all of the debris, sludge, and grime from the transmission, and then add new fluid that’s going to continue to clean the system, the debris, sludge, and grime will just be mixed back in with the good fluid. So, when we perform our transmission fluid service, we add an effective cleaner into the system prior to servicing the fluid and we get the fluid up to operating temperature. We then run the transmission through all the gears so we can open and close all of the valves in the transmission. Once we have completed those steps, we begin the actual servicing step, where we flush double the fluid capacity through the system. What that does is remove the old fluid, flush new fluid through it to capture any leftover spoiled fluid or debris, and finally, replace it with brand new fluid. Once we’ve completed that step, we add a conditioner to the system to ensure long-lasting lubricity for the next 30,000 Miles. 


If you need any help with this service or others, we are happy to give you a hand here at Honest Wrenches. Visit our website, give us a call, or even stop by, and we can answer any questions you may have, and provide you with any necessary service. 

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