How to Change the Transmission Fluid on a 2003 Toyota Tacoma

by Tonya Cunningham
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Transmission fluid provides lubrication for the various components of your transmission. When transmission fluid gets old or goes bad due to environmental factors such as dirty roads or highly polluted areas, your transmission may begin to stick, squeak or hesitate when shifting. Replace your 2003 Toyota Tacoma's transmission fluid approximately every 20,000 to 30,000 miles. Although transmission fluid replacement is one of the more time consuming fluid changes in a vehicle, it is still a task that can be easily carried out by a mechanically-inclined Tacoma owner.

Step 1

Run your Tacoma truck for at least 10 to 15 minutes prior to changing the transmission fluid. If the old fluid is warm, it will empty out of the transmission faster than cold, thick fluid.

Step 2

Raise your Tacoma using a car jack and jack stands so that it is horizontally even with the ground beneath it. Uneven elevation causes problems in both reading the dipstick fluid level as well as creating a hazard while removing the transmission pan, because fluid can spill onto you during the procedure.

Step 3

Place your drip pan on the ground directly beneath the drain plug portion of the transmission pan. Your transmission pan can be easily identified as the square metal object closer to the driver's side wheel under your truck, with numerous bolts holding it in place.

Step 4

Use your 24mm socket wrench to unscrew the drain plug at the side of the transmission pan. Transmission fluid will start coming out of the plug immediately, so keep your face away from the plug.

Step 5

Wait about 10 minutes to be sure that the majority of loose fluid has emptied.

Step 6

Unscrew the bolts surrounding the transmission pan. When you get to the last few bolts, keep the pan level so that no fluid from the bottom of the pan drips onto you.

Step 7

Clean both the inside and outside of the transmission pan using your degreaser on the shop rag. Do this thoroughly so that the new fluid does not become contaminated with harmful particles from the old fluid.

Step 8

Lift the transmission pan back into its original position under the transmission.

Step 9

Wind each bolt with your fingers just enough to hold the pan up.

Step 10

Torque the bolts down securely using your 24mm socket wrench. Fasten the bolts flush with the transmission so that no openings are exposed where any fluid could leak out.

Step 11

Open the hood of your truck and locate the transmission's fill plug, near the driver's side of your Tacoma. When you unscrew the fill plug, you will see that the dipstick is attached to the cap.

Step 12

Turn your ignition key so that your Tacoma is running during this portion of the procedure. This allows the fluid to flow warm, providing a more realistic reading of the transmission fluid, considering that the truck will be running when the fluid is in use.

Step 13

Pour the first qt. of transmission fluid into the fill plug using a funnel for accuracy.

Step 14

Push your emergency brake to the floor and shift the car into various gears for a few seconds at a time. Your foot should also be on the brake pedal for extra safety during this step. Putting the car in different gears forces the transmission fluid through each part of the transmission system and opens more space for more fluid in the fill plug area.

Step 15

Pour the other qt. of fluid into the fill plug, but go slowly so that there is no overflow. The entire second qt. may not fit into the transmission and you do not want to risk spilling the fluid, creating a messier area to clean up.

Step 16

Shift the car's gears once more before cleaning up, to ensure that the transmission fluid is completely lubricating every gear in the transmission.

Step 17

Finish the transmission fluid change by lowering the car jack, removing the jack stands, replacing the fill cap and closing your truck's hood.

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