Transmission Fluid Filler- Meaning and How to Use It?

An ATF fill can be quite costly. With the transmission fluid filler, you can save on these costs. Learn how the tool works and how to use it here!

Transmission fluid filler with adapters
Transmission fluid filler with adapters

Does your car have a transmission dipstick? If not, then you may want to invest in a transmission fluid filler. The transmission filler presents an innovative way to add ATF to the sealed transmissions of most modern cars. If you’re wondering what this filler tool is and how it works, stay put. This article will cover everything that matters about its working and application. Continue below to find out what a transmission filler tool does and why you need to invest in one.

What is a Transmission Fluid Filler?

The transmission fluid filler is a device that allows you to fill a sealed transmission. Most modern cars are built without a transmission dipstick. This makes them difficult to fill, unlike older models that can be filled from the top using a funnel.

The transmission filler is basically a pump that will send transmission oil via the fill plug located under the car. Although styles vary, the most common type of this device is a manual fluid pump that you operate with the hand.

Advanced designs are automatic and use an air compressor, but these are not popular with DIY car owners. The manual type is the most common. It’s also the most usable type of transmission filler pump- and the most affordable.

Transmission filler kit with the adapters in a case
Transmission filler kit with the adapters in a case

The Transmission Fluid Filler Kit

The transmission fluid filler is normally sold as a kit. That means several other pieces besides the pump itself. With the kit, an auto technician or DIY-er is able to fill the transmissions of many different cars without needing to switch to a different pump. Here, a list of the components in a typical transmission fluid filler kit.

Transmission Fluid Filler Pump

The transmission fluid filler pump is the main unit in the kit. It consists of the following: a handle to operate the pump, the pumping mechanism, a gauge to provide pressure readings, and a reservoir to hold the fluid being pumped. Other parts of the fluid filler pump include a valve to safely release pressure after using the device and a fluid inlet through which to add transmission oil.

Transmission Fluid Filler Tube

This is the tube that links the pump to the transmission when using the tool on your car. It carries the pumped fluid from the reservoir to the transmission. The most common size for the tube is 5 feet length and 7.5 mm diameter. An automatic transmission fluid filler kit that uses shop air will have additional tubes (extraction and filler tubes).

Transmission Fluid Filler Adapters

In order to be compatible with different vehicle makes and models, the kit will also come with a range of adapters, some universal and others OE. These adapters connect to different fill plugs or openings. The pump unit often includes a belt that wraps around the reservoir to hold the adapters. Some versions of the transmission filler kit come with plastic cases for the different adapters.

Why do you need a Transmission Fluid Filler Tool?

Transmission fluid gets lost through evaporation or even leaks in the seals. Low levels of the fluid can cause various problems. It will also lead to noticeable symptoms. A transmission fluid fill up then becomes necessary. In some cars, that involves using a funnel.

In some modern cars, you cannot use a funnel to add gear oil as the filling or injection opening is located under the car. Here is where you need the transmission oil filler tool. The tool comes with a pumping unit and tube to make everything convenient and less cumbersome.

Connecting the transmission filer adapter
Connecting the transmission filer adapter

How to Fill Up Transmission Using the Filler Pump

A transmission fluid filler pump will enable you fill or refill an automatic transmission. The device is itself straightforward to use, and you shouldn’t encounter any challenges. You only need to check and confirm low levels of the fluid to be topped up. Here now, is how to fill up transmission fluid using the filler pump.

Note: It’s important to know what type of transmission fluid you needed before filling. Not all fluids are compatible. To find out what oil to use, consult the car manual.

Step 1: Drain Transmission Fluid

  • Open the draining plug located under the car using the appropriate tools.
  • Allow the transmission fluid to drain out.
  • When all oil has drained out, replace the plug. You may insert a new one if necessary.

Step 2: Fill Fluid Filler Reservoir

  • Connect the transmission fluid filler tube to the unit.
  • Open the transmission filler cap on the top of the unit.
  • Using a funnel, add an appropriate amount of the transmission to the reservoir.
  • Replace the filling cap and turn the valve at the end of the tube to “off” position.

Step 3: Connect Transmission Fluid Filler

  • Identify the transmission fluid fill adapter that fits your vehicle.
  • Next, locate and unscrew the transmission fill plug.
  • Insert the filler tube (with the adapter connected) into the opening

Step 4: Pump Transmission Fluid Filler

  • Using the handle on the top, pump the unit to introduce pressure.
  • Bes sure to watch the pressure gauge so you do not exceed the pressure.
  • For most applications, the pressure limit is 20 psi. Do not go beyond that.

Step 5: Fill the Transmission with Oil

  • Open the valve to allow fluid to flow into the transmission.
  • Close the valve when fluid starts to drip out of the filling/injection hole. It shows the transmission is already filled.
  • Remove the tube and replace the plug.
  • Press the pressure release valve on the fluid filler pump to remove any pressure that may have remained.


The transmission fluid filler is a tool that you cannot afford to lack in your garage. It lets you take care of your car’s sealed transmission fluid without much effort. The tool is available in different sizes, designs, and several other features. Be sure to look out for specifications that fit your application. By ensuring the adapters for your type of car are included in the kit, for example, or if the reservoir size fits your requirements, among other considerations.

Leave a Comment or Questions

About Author
Richard Johnson
Richard Johnson

Richard Johnson is a writer and a content marketer who works for hand in hand with Sunbright Automotive Tools. Beforehand, Richard Johnson worked for multiple industries that had helped both small and big businesses to build better brands online through web page contents that productized services.

Latest Posts
Contact Us
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Sign up for our Newsletter

Shopping cart


No products in the cart.

Continue Shopping

Need Help From Sunbright?

I’m Here To Assist You

Something isn’t Clear?
Feel free to contact me, and I will be more than happy to answer all of your questions.