The transmission cooler on your Nissan Pathfinder is a device that is mounted between the radiator and the transmission that provides extra cooling protection for your transmission. Transmission coolers are typically installed on larger vehicles, like your Pathfinder, particularly if they are used for towing. If the transmission cooler on your Pathfinder goes out, it should be replaced immediately. Replacement time is approximately an hour to two hours. Replacement transmission coolers for your Nissan can be purchased either from your Nissan dealership.
Jack up your Pathfinder's front end and put jack stands in place under the frame. Seat your Nissan on the jack stands so that it is secure.
Open your Pathfinder's hood and remove the mounting bolts that hold your transmission cooler to the back of your radiator. Use your socket set to remove these mounting bolts.
Use the line wrench to remove the bottom cooler line that runs from your radiator to the bottom of your transmission cooler.
Use the line wrench to remove the top cooler line that feeds from the top of your transmission cooler to your transmission.
Pull the old transmission cooler out and slide the new into place inside your Pathfinder's engine compartment.
Twist the top cooler line in place by hand and then tighten it with your line wrench. Do the same to install the lower cooler line.
Replace the mounting bolts on your new transmission cooler and tighten them down with your socket set.
Lower your Pathfinder from the jack and jack stands.
