How to Remove Transmission Cooler Lines

by John Stevens J.D.

Transmission fluid not only allows the transmission to change gears, but also to prevent the transmission from overheating. In addition, the fluid acts as a lubricant to prolong the life of the transmission's internal components. As the fluid circulates through the transmission, it gradually increases in temperature. To cool the transmission fluid, the fluid is routed to the radiator at the front of the vehicle via two cooler lines. Whether the transmission is to be removed or the transmission cooler lines are to be replaced, the first step in either process is to remove the cooler lines.

Step 1

Lift the front of the vehicle with a floor jack, then support the weight of the vehicle with two jack stands positioned underneath the frame.

Step 2

Lift the rear of the vehicle under the differential with a floor jack, then support the weight of the vehicle with one jack stand positioned under each axle at the differential.

Step 3

Drain the transmission fluid from the bottom of the transmission at the transmission's pan. Many pans have a drain plug that can simply be removed with a wrench. Pans that do not feature a drain plug must be removed. To remove the pan, loosen the bolts that secure the pan to the bottom of the transmission, then insert the blade of a flathead screwdriver between the pan and the transmission. Twist the screwdriver to break the pan's gasket from the transmission. Once the transmission fluid has stopped draining, remove the pan's bolts to remove the pan.

Step 4

Open the hood and find the two transmission cooler lines, which lead to the bottom of the radiator. Trace both lines underneath the vehicle to the transmission.

Step 5

Remove the two transmission cooler lines from the side of the transmission with a flare nut wrench. To use the wrench, slide the open end of the wrench over the cooler line, then slide the wrench down the line until it reaches the nut used to secure the line to the transmission. Use the wrench to loosen the nut located at the end of each line, then pull the line away from the transmission to remove it.

Step 6

Remove the two transmission cooler lines from the bottom of the radiator. These two lines can be accessed either from underneath the hood or underneath the vehicle. Use the flare nut wrench to remove the lines in the same manner used to remove the lines from the transmission.

Step 7

Slide both transmission cooler lines away from the vehicle, pulling each line from the transmission rather than the radiator to complete the removal process.

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