I believe the top line is the output from the transmission and the lower one is the return. Easy way to tell is to just remove one line, then have someone start the engine just long enough to verify which way the fluid flows. Say you remove the upper line and fluid comes out of it, that is the output, if fluid comes out of the cooler it's the return line. I always do it that way because I've run into a few where someone reversed lines or replaced an OEM cooler with an aftermarket unit and just cut the lines. If you are planning on adding a cooler to this car, add it in the return line if you are in a colder area, that helps the transmission warm up in the cold. If you are in a warm climate you can just use a larger external cooler to keep the temperature down and not connect to the stock unit at all.
Apr 7, 2020 at 9:17 PM
