Transmission Fluid Change: Ultimate Guide

Well, do you enjoy paying $5,000 for a new transmission or not?

A BMW automatic transmission.
Depositphotos

Your car’s fluids are its lifeblood. When they get old, brown, and sludgy, it’s detrimental to the vehicle and to the size of your bank account. One such necessary fluid that people often dismiss is your transmission fluid. This thick oil keeps the transmission’s mechanicals lubricated, and if it’s ignored, you’ll potentially be staring down a massive repair bill 

There are thousands of online tutorials and guides about why you need to change your oil, but not too many on why you should absolutely change your transmission fluid. To better inform readers and DIY’ers everywhere on the importance of this crucial liquid, The Drive’s crack informational team has put together a guide answering all your most important questions about transmission fluid.  

Taking up the charge, we’ve dedicated Guides and Gear’s channel today to explaining just exactly what happens when you don’t change your transmission fluid, as well as how to change it yourself. 

Socket wrench at the ready!

The guts of an automatic transmission.
Depositphotos

The guts of an automatic transmission.

What Is Transmission Fluid?

Transmission fluid is the viscous oil that allows the transmission to function without failure. By lubricating the transmission’s internals, the fluid prevents heat build-up and wear and tear of metal-on-metal. Transmission fluid is typically colored red or green to help DIYers distinguish it from conventional motor oil. 

Transmission Fluid Change: What Happens If You Don’t Do It?

Most transmission fluid is designed to last for up to 100,000 miles. There are a few with higher limits, though it’s still recommended you change your fluid at 100,000 miles or close to it. 

Depending on the level of abuse you dole out, unchanged transmission fluid could seize, evaporate, seep out, and cause catastrophic transmission failure. So if you don’t want to be out a couple thousand dollars, it’s best you check your transmission fluid from time to time. 

Here’s How To Change Transmission Fluid

First, there are a few things you need to know.

Transmission Fluid Change Basics

Estimated Time Needed: Half-hour 

Skill Level: Beginner

Vehicle System: Transmission

Safety

Working on your car can be dangerous and messy, so here’s exactly what you’ll need to ensure you don’t die, get maimed, or lose a finger.

Everything You’ll Need To Change Your Transmission Fluid

We’re not psychic, nor are we snooping through your toolbox or garage, so here’s exactly what you’ll need to get the job done. 

Tool List

Parts List

Organizing your tools and gear to change your spark plugs so everything is easily reachable will save precious minutes waiting for your handy-dandy child or four-legged helper to bring you the sandpaper or blowtorch. (You still won't need a blowtorch for this job. Please don’t have your kid hand you a blowtorch—Ed.)

You’ll also need a flat workspace, such as a garage floor, driveway, or street parking that’s also well-ventilated to change your transmission fluid. Check your local laws to make sure you’re not violating any codes when using the street because we aren’t getting your ride out of the clink.4

Transmission fluid draining from the pan.
Depositphotos

Transmission fluid draining from the pan.

How to Change Your Transmission Fluid

Let’s do this! 

  1. Lift the car if necessary. You can read The Drive’s How To Lift a Car here
  2. Pop the hood, find the transmission fluid cap, and remove the cap.
  3. Locate the transmission’s fluid pan. 
  4. Place the drain pan underneath the pan.
  5. Using the socket wrench, remove the transmission pan’s bolts.
  6. Let the fluid drain completely out of the transmission.
  7. Install the new transmission gasket. 
  8. Reconnect the pan’s bolts.
  9. Using the funnel, pour in the prescribed amount of transmission fluid. 
  10. Remove the funnel and put the cap back on. 

You’re done!

Get Help With Spark Plugs From a Mechanic On JustAnswer

The Drive recognizes that while our How-To guides are detailed and easily followed, a rusty bolt, an engine component not in the correct position, or oil leaking everywhere can derail a project. That’s why we’ve partnered with JustAnswer, which connects you to certified mechanics around the globe, to get you through even the toughest jobs. 

So if you have a question or are stuck, click here and talk to a mechanic near you.

Inside the transmission fluid pan.
Depositphotos

Inside the transmission fluid pan. 

FAQs About Transmission Fluid

You’ve got questions, The Drive’s informational team has answers!

Can I Check My Own Transmission Fluid Level?

You can! Underneath your hood is a transmission fluid dipstick, similar to an oil dipstick, that allows you to check the level and condition of your fluid.

How Often Do You Need To Change Transmission Fluid?

As mentioned, most transmission fluid will last around 100,000 miles. But it’s important to periodically check your transmission fluid, an act that takes all of a few seconds and could save you thousands of dollars in repair bills.

How Much Does It Cost To Change Transmission Fluid?

If you have a dealership or third-party mechanic do the transmission fluid flush, you’re looking at a range of $80-$250. DIYers will have considerably smaller bills, ranging from $25-$50 depending on how much fluid your car takes.

Featured Products

Castrol Transmax Dex/Merc ATF

ACDelco Dexron VI Synthetic ATF

Red Line GL-4 Manual Transmission Lubricant

Got a question? Got a pro tip? Send us a note: guidesandgear@thedrive.com