Extend the life of your engine by changing transmission fluid. It's much easier by using a special transmission fluid pump, and you'll save $100 in shop costs when you do it yourself. We show you what you need and how to do it.
By the DIY experts of The Family Handyman Magazine
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$20 – $100
Overview: How to change transmission fluid
Buy a special transmission fluid pump
Transmission fluid pump
This transmission fluid pump is the key to saving you time and money when you change transmission fluid.
You should change your automatic transmission fluid according to the manufacturer’s recommendation— whether that’s 30,000 or 100,000 miles. A transmission fluid change will add tens of thousands of miles—which could be years of service—to a transmission’s life expectancy and prevent repairs costing thousands down the road. Read on to learn how to change transmission fluid.
A transmission flush-and-fill from a shop will cost you $149 to $199. But you can do it yourself and save about $100. Draining the old fluid has always been a messy, ugly job. That’s because it has meant lying under the car, “dropping” the pan—and then getting drenched in fluid. But here’s a new way to change your fluid without going under the car and without spilling a drop. The procedure takes less than 30 minutes.
How to Replace Transmission Fluid
The trick on how to drain transmission fluid is to work from the top, sucking out the old fluid up through the filler tube. Then refill with fresh fluid. A hand-operated vacuum transmission fluid pump makes the job simple and clean. You can remove one-third to one-half of the fluid from the transmission at a time. The rest will remain in the torque converter and the transmission cooler. So do the procedure three times at one-week intervals to replace nearly all of the old fluid. The little leftover old fluid will be diluted with plenty of fresh new fluid.
Some manufacturers recommend replacing the filter every time you change transmission fluid. Go with what your dealership recommends. Note: But if your transmission pan is leaking, you should either “drop” the pan and replace the gasket, or take it in for service.
How to Recognize Old Fluid
New fluid is bright red. Old transmission fluid turns brown as it degrades—time to change.
How to change the fluid
Photo 1: Insert the vacuum tube
Remove the dipstick and insert the vacuum tube until you feel it “bottom out” on the bottom of the transmission pan.
Photo 2: Pump up the tank
Close the latch on the vinyl hose and pump up the transmission fluid pump’s vacuum tank with 30 to 50 strokes of the plunger.
Photo 3: Draw out the fluid
Release the latch on the hose and wait while the vacuum draws the old fluid out.
Photo 4: Refill with new fluid
Read on the tank the amount of fluid you withdrew and refill the transmission with that amount of new fluid.
Follow the photo series for complete step-by-step instructions.
Buy the Right Stuff
Carmakers have made major improvements to transmission fluids in the past two years. Contact the dealership parts department to see if your car requires a newer fluid. Then call auto parts stores until you find one that stocks it. If you strike out, bite the bullet and buy it from the dealer.
Video: How to Check Transmission Fluid
Rick Muscoplat, an editor for Family Handyman, will show you how to check your transmission fluid to prevent damage to your transmission in our video tutorial. Make sure you are not driving around with low transmission fluid.
Required Tools for this Project
This project requires a special fluid pump. Plus, wear plastic gloves.