Engine, trans, or both?
Most of the time they are mounted up in front of the a/c condenser/ radiator, lines pretty much out of the way.
There are also some remote trans coolers that mount back in the rear side of the Jeep, between the frame and trans. Serious system, has it's own cooling fan. Again designed to be out of the way. Jerry did a nice write up on this up in the TJ section.
97 Sahara, 74 Renegade, 72 CJ5, 55 Willy's (the Beast) Boss 302, 6:34 gearing, Bose 901 speakers.
God I miss that Jeep. Forgot the kinda Jeep, 80 SX4.