If you do NOT have an auxiliary trans cooler, then look for two lines that run from the tranny up to the lower part of the radiator. They screw into the radiator and are cooled inside the radiator. One line brings the hot fluid to the radiator and other returns the cool fluid back to the tranny. Crawl under and just follow then from the tranny forward. They usually run right beside one another. If you have an auxiliary tranny cooler the lines still run from the tranny but at some place they connect to a cooler usually located IN FRONT OF THE RADIATOR. I said usually. Some peopel mount tranny coolers in different places. An auxialiary tranny cooler looks like a mini radiator with the fins and all. There are two lines .......one is the inlet and one the outlet just like the radiator. SOmetimes I have seen the lines going from the tranny and the inlet line goes into the radiator, then comes out of the radiaotr via the outlet, then the outlet line goes to the auxiliary inlet line in front of the radiator and then from the outlet the line runs all the way back to the tranny. This way the fluid is cooled in the radiator as well as the auxiliary cooler. Finding the two metal lines that come from the tranny is the key and follwing them.