How to Replace Transmission Fluid

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The transmission is typically one of the most expensive components in a car. When transmission fluid starts getting old, it can lose some of its lubricating ability. Not having the fluid do its job can cause the internal gears in your transmission to wear, which can only be fixed by rebuilding the whole transmission – a process you don’t want to be a part of. Some manufacturers don’t recommend the replacement of transmission fluid at all; they claim it lasts for the life of the vehicle. However, most manufacturers recommend you replace the transmission fluid between 30,000 and 60,000 miles.

If you are looking for the transmission’s dipstick to measure the fluid’s level, you may be looking for a while. Most modern cars don’t come equipped with one. The transmission features a fill plug and a drain plug on the bottom of the car. The fill plug works as your dipstick. To measure the transmission’s fluid level, remove the fill plug and put your finger in there. The fluid should be right there. If you can’t feel the fluid, it is too low. Before draining the old fluid, be sure to have a fluid pump handy. The fluid pump is the only way to refill the transmission with fluid, as it will be working against gravity. However, if your transmission is equipped with a dipstick, you can use a funnel and fill it from there.

If your car has more than 100,000 miles stacked on it, or if you do a lot of heavy-duty driving, such as towing and hauling, be sure to replace your transmission fluid between 15,000 and 30,000 miles. Read on to learn how to replace your transmission fluid.

Tools Required:

Jack
Jack stands
Socket
Allen wrench
Hex bit
Fluid pump
Drain pan
Transmission fluid

Use your jack to raise the front of your car, just enough so you can work from under there. Most jack points are behind the front wheels or in front of the rear wheels, depending on which side you are raising. For the ultimate accuracy, raise both the front and the rear, then secure them with jack stands – at least one jack stand on each side.

The fill plug and the drain plug can vary from one model to another. Use your socket, Allen wrench, or hex bit to remove the fill plug first. The fill plug is always higher than the drain plug, and the drain plug is always on the bottom, or at least lower than the fill plug.

Place the drain pan under the drain plug, and with the fill plug removed, remove the drain plug and let the transmission drain completely.

Close the drain plug and then torque it to the proper torque specs in your owner’s manual. Fill your fluid pump with fresh transmission fluid, then connect it to the filler hole. Pump fluid into the filler hole until it overflows, which is how you know your transmission is full. Close the fill plug and torque it appropriately.

Pro Tip

Some rare models require you to drop the transmission pan in order to replace the fluid. In this case, be sure to find out the torque specs for all the bolts holding the pan in place, and then drop the whole pan to replace the fluid.