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How to Fill the Transmission Fluid on a Ford F-250

by Kyle McBride

The Ford F-250 truck is a 3/4-ton pickup. That means the cargo-carrying capacity--the amount of cargo that the pickup is capable of carrying in its cargo bed--is three-quarters of a ton, or 1,500 pounds. The drivetrain of the F-250 includes either a manual transmission or an automatic transmission. Mounted to the rear of the engine, the transmission transfers power from the engine to the drive wheels (the rear wheels) of the truck. The transmission is filled with fluid, and the fluid level must be maintained in order for the transmission to work as intended.

Automatic Transmission

Step 1

Start the engine, preferably without touching the accelerator pedal. Set the parking brake and put the transmission in neutral. Allow the truck to run for at least two minutes.

Step 2

Open the hood, then grasp the transmission dipstick and pull it out of its tube. The transmission dipstick is typically on the passenger side in the rear of the engine compartment.

Step 3

Wipe the dipstick with the rag, then reinsert it into the tube. Press the dipstick into the tube until it is fully seated, then pull it out again. Look at the tip of the dipstick and note where the transmission fluid has wetted the dipstick (if at all).

Step 4

Insert the tip of the transmission funnel into the tube. Add half a quart of transmission fluid. Wait a moment to allow the transmission fluid to drain down the tube, then repeat step 3. Repeat until the dipstick is continuously covered with transmission fluid up to the middle hole.

Step 5

Press your foot on the brake pedal, then move the transmission shifter into each gear of the transmission. Return the transmission to neutral.

Step 6

Repeat steps 3 and 4 until the transmission fluid touches the middle hole on the dipstick.

Drive the truck for about 15 minutes. Park on a level surface, then check the fluid level on the dipstick. Repeat steps 3 and 4 as needed until the transmission fluid is at or just below the "Do Not Add" mark on the dipstick.

Manual Transmission

Step 1

Sidle under the truck.

Step 2

Locate the check/fill plug on the side of the transmission. The check/fill plug is the upper plug on the transmission case on the passenger side if your transmission is a four-speed, or on the driver's side if your transmission is a five-speed. Wipe all dirt and foreign matter from the plug and from around the plug.

Step 3

Remove the check/fill plug with a wrench or breaker bar. (If fluid begins oozing out while you are removing the plug, reinstall the plug; the transmission is full.)

Step 4

Insert the tip of your pinkie finger into the hole from which the plug was removed. Remove your finger from the hole, then observe your fingertip. (If there is fluid on the tip of your finger, reinstall the plug; the transmission is full.)

Step 5

Insert the end of the hand pump into the hole, then pump gear oil into the transmission. Pump slowly while observing the hole. Remove the pump and reinstall the check/fill plug as soon as fluid begins oozing out of the hole.

Wipe any spilled gear oil off the transmission with a rag.


  • If the transmission is empty, such as after having the fluid drained for service, add three quarts of fluid to start.
  • If you need more room under the truck, jack the truck up, then put it on jack stands.


  • Do not overfill the transmission. Do not add fluid if the fluid level is at the "Do Not Add" mark on the dipstick.

Items you will need

  • Transmission funnel
  • Shop rag
  • Automatic transmission fluid
  • Mechanic's tools
  • Hand pump
  • Gear oil

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