11 months ago

How to Change Transmission Fluid and Filter – DIY Guide

Gas is not the only thing your car needs to run. A lot goes into making a car operate right and have a long service life. One of the most important components of your car is the transmission and its health depends on the quality of the transmission fluid in it. Let’s see why transmission fluid is important and how you can change it at home. 

Transmission Fluid – The Basics

Transmission is the part of a vehicle that acts as a bridge for transmitting the power generated by the engine to the wheels in order to drive. Transmissions can broadly be classified as manual or automatic. 

In a manual transmission, the transmission fluid is there to make sure that there’s no excess wear of the components of the transmission like the gears and bearings. In an automatic transmission, however, the fluid has a more important job.

Why is Automatic Transmission Fluid Change Such a Big Deal? 

Automatic transmissions have a component called the torque converter. It is a hydraulic machine that receives the torque from the engine and converts it into the motion of the car. This conversion is made possible by the flow of the transmission fluid through the torque converter. It means that the transmission fluid is responsible for transferring every last watt of power produced by the engine to the wheels of the car. 

As a result, the transmission fluid in the automatic transmissions undergoes a lot of stress and wears out quicker than that in manual transmissions. 

When to Change Automatic Transmission Fluid and Filter

This mainly depends on the make and model of the car you have and your driving style. Most cars need a transmission fluid and filter change between 30,000 to 60,000 miles. However, the actual automatic transmission fluid change frequency can be different – more on that in a bit. 

Transmission Fluid Filter Change – More Important than You Think!

The most common mistake people make while changing the transmission fluid is not changing the transmission fluid filter. A transmission fluid filter is the component of the system that traps all the bits of metal and other debris formed during the operation of the transmission and does not let it freely float in the transmission and do harm to the components of the system. The transmission fluid filter must always be changed with the fluid or the whole process will be in vain, as the contaminated filter will destroy the new fluid. 

Changing Transmission Fluid

Now that you know the importance of transmission fluid for your car, let’s see how to change transmission fluid and filter. 

Prerequisites for Transmission Fluid Change

Before you get your hands dirty and start undoing screws to change the transmission fluid, here are some of the things you need to make sure of.

  • Make sure that your car actually needs a transmission fluid change. Some cars indicate in the instrument panels, while for others you need to consult the owner’s manual. If you are wondering if you need to change the automatic transmission fluid on your car or not, we’ll be telling you the signs that indicate you need this at the end of this post.
  • Let the car’s engine and transmission cool down for a couple of hours before starting the procedure. Normally the engine can be hot enough to give you third-degree burns. 
  • Never work under the car alone. Make sure you have someone around so that in case of any emergency, you can call for help.
  • Consult the owner’s manual or search online to look where to drain the transmission fluid from, and where to refill it. Failing to do so may result in you replacing some other fluid with the transmission fluid and that’s the last thing, you need to do to a car.

Things Required for Changing Transmission Fluid 

After you have decided to change the transmission fluid and filter on your car, you need to have the following. Most of these instruments can be used for a variety of purposes, so buying them will be a good investment if you want to keep doing DIY projects on your car. Alternatively, you can rent them from a local auto store.

  • A hydraulic car jack or a pair of ramps to elevate the car high enough to work on it
  • A wrench to open the transmission fluid pan to drain the old fluid
  • A catch pan to collect the old transmission fluid
  • Transmission pan gasket to seal it
  • Transmission fluid filter
  • Transmission fluid, as specified by the car’s owner’s manual.
  • A funnel to pour the oil

Transmission Fluid and Filter Change Steps

Once you have all the required stuff, here are the simple steps that you need to execute for transmission fluid and filter change.

Elevate the Car

The first step of the process is a straightforward one, but it is potentially the most dangerous one too. Elevating a car is a very simple thing, but a little carelessness in this process can spell disaster for you. Here are some things that you need to take care of while doing this.

  • Make sure that the car is on level ground and not on a slope when you start lifting it with a jack.
  • Use a jack that has a capacity more than the weight of the vehicle you are working on.
  • Put the car transmission in Park, engage the e-brake, and block the rear wheels with a brick or a log.

Locate the Transmission Fluid Pan and Drain it

Now is the time for getting your hands dirty. Locate the transmission fluid pan and make sure it is not hot. Use a wrench or spanner to undo all the bolts holding it in place and keep a catch can below it to avoid spilling the used transmission fluid. Once the pan comes off the car, let all the fluid drain before proceeding.

  • Pro Tip: When finding the transmission fluid pan, go for the one that has no drain plug. The one that has one is the engine oil pan, and not the transmission one.

Replace the Transmission Fluid Filter 

After all the fluid has been drained, drop down the filter that typically sits just above the pan and replace it with the new one. Make sure that the filter you are using is compatible with your car as well as with the fluid you are using.

Replace the Gasket 

The next step is to replace the gasket that seals the joint between your transmission’s body and the transmission fluid pan. Be sure to remove all bits of the old one before putting on the new one for optimum sealing. If you cannot find the gasket for your car, you can use silicone to make a gasket by applying it to the pan before reinstalling it.

Install the Transmission Fluid Pan

After the gasket situation has been taken care of, place the transmission fluid pan back and tighten all the screws all the way to secure the pan in place.

Add the New Transmission Fluid 

After you are sure that the pan is in its place and there is no leakage (and the gasket is correctly installed), use a funnel to add the new transmission fluid to the transmission. It is of paramount importance to use the exact same transmission fluid specified by the manufacturer or you’ll do more harm than good to the vehicle.

Dispose of the Old Fluid

The used transmission fluid is full of chemicals that are detrimental to the health of humans,  animals, and the environment. Collect all the used fluid in sealed containers (you can use the one the new fluid came in) and take it to your local recycling center to be properly disposed of.

Frequently Asked Questions About Transmission Fluid Change

How often do I change transmission fluid and filter?

This mainly depends on the car you have and the transmission fluid you use. Most of the modern cars come with full-synthetic transmission fluid that has a life of up to 60,000 miles. If you drive too aggressively or live in a hot climate you may need to change the fluid more often. 

When should I change my transmission fluid and filter?

You should change the transmission fluid in case any of the following are true:

  • Your car has completed the recommended mileage for a transmission fluid change.
  • Your car’s instrument panel shows a warning about changing the transmission fluid.
  • Your car revs higher than it should at any given speed.
  • Your car’s acceleration is not consistent. 
  • Your car struggles to negotiate slopes.
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