I assume you mean a trans cooler. You should be able to mount one of the finned heatsink tube types under your car (on the frame) some place. There are also fairly small units units that might fit behind your grill. There is one on my wife's Mountaineer that is only about 3" x 8", mounted behind the grill to the side of the condenser. I had one mounted on my old Z1, it had a lot less space for mounting than your 31.

Check out Speedway Motors they have a number of different types.