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Transmission fluid has been a subject of car maintenance debate for a long time, with some vehicles even labelling their transmission dipstick as something that should not be changed.  But as technologies have improved engines’ durability and longevity in the modern day, with vehicles easily exceeding over 100,000 miles and beyond, it has become commonplace to change your transmission fluid to keep up with the extended life of your car. Similar to motor oil, transmission fluid is important to reduce transmission friction and curb the wear and tear of the transmission gears. It may be a longer lasting fluid compared to the frequent changes that motor oil requires, but it does deteriorate over time.  We give you the information of how to know when your transmission fluid needs a change, and how you should do it.

How to read the health of your transmission

Transmission fluid comes in a variety of colors, ranging from blue, yellow, and green to the more commonplace red.  All these options will start out fairly pale and bright, with the red appearing more pinkish, so that it’s fairly easy to tell when your fluid needs changing based upon the color.  The more dark and brown the color appears, the more the fluid has been burnt and contaminated by transmission debris build up. There’s also the scent! Transmission fluid is interestingly sweet smelling, noticeably growing more burnt the longer the fluid has been in use. You should be keeping an eye out for metal particles, any kind of milkiness, or air bubbles. These signs hint to internal damage your transmission may be experiencing, any kind of contamination, or a leak in your transmission line.  

Fortunately says Ted Britt Chevrolet (Sterling, VA), checking the color of your transmission fluid is easily done with your engine’s transmission dipstick. This is located near the transmission fluid pipe. Generally, front-wheel drive vehicles will have the dipstick near the front of the engine, while rear-wheel drive vehicles have it towards the back of the engine.  Same to how you check the level and cleanliness of your motor oil, you wipe off the dipstick then reinsert to gauge how much fluid you have within your transmission. The color can then be read on your paper towel or rag. The dipstick will have two notches labelled either “hot and cold” or “full and add.” Fluid levels should fall between these two notches.

How often should you change your transmission fluid

The timeframe between changing your transmission fluid differs between manual and automatic transmissions.  Each brand usually specifies their own time period within your owner’s manual, but generally, mechanics suggest to change manual more frequently due to the greater stresses and moving parts they’re built with, as well as the use of traditional gear oil. Changes are typically between 30,000 and 50,000 miles. Automatic transmissions can be anywhere between 50,000 miles and 150,000 miles, depending on the vehicle’s performance index and power demand. Particularly vehicles that tow or haul big weights, extra strain generates more friction and heat that will more quickly deteriorate your transmission fluid.

How do I change my transmission fluid

If you’re an industrious individual who likes to do their own car maintenance, changing out your transmission fluid is similar to how you change out your motor oil. Again, things differ between manual and automatic transmissions. For an automatic transmission, you’ll locate the transmission beneath a jacked up vehicle and remove the bolts from one side of the transmission pan. Then, you can gradually loosen the bolts from the other side to control the rate of flow out of your transmission to prevent messes.  Once most is out of the transmission, you’ll be removing the pan completely to change out the gasket. This lets you clean out the pan and gasket housing, too, keeping gunky buildup at bay. You’ll also want to change out your transmission filter. This is attached with a separate bolt of the transmission.

Your owner’s manual should specify which filter model your vehicle needs to replace this old one.  Once your gasket housing is clean and your gasket is replaced, and the bolts are secured back on, you’ll refill your transmission fluid from under your hood at the transmission fluid line indicated by your transmission fluid dipstick tube. Use a funnel to cleanly refill your fluid through this tube, then run your vehicle to adequately warm and circulate the new fluid before checking your dipstick to ensure you’ve poured in enough transmission fluid.  

Manual transmission changing is slightly easier, as engineers have catered to the need to more frequently exchange the transmission fluid with a plug instead of a bolt, for most vehicles.  The gasket and filter last for much longer than for how often you’ll be changing your transmission fluid, so you don’t need to remove your transmission pan and exchange parts every single time. What is different is the fill up process. Once the fluid is drained, you’ll be using an oil pump to replace the fluid with new product.  

Keeping your transmission properly lubed and clean is just as important as ensuring you exchange your motor oil on time.  Build up and degradation of these fluids is natural from any engine, and allowing this debris to accumulate will impact your engine’s performance and ultimately cut your vehicle’s healthy years short. Keep your vehicle in tip top shape and make sure you change your fluids on time! If you’re not sure about the products or time period your engine needs, it’s best to contact either your dealership or your local mechanic to get some expert insight on how to best care for your car.  

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