Transmission cooler line leaking

1999 Chevrolet S-10 transmission cooler line is leaking. The fluid is running down the line and dripping on the ground under the passenger side of the truck.I am not sure if it has came loose or if it may have a pinhole in it somewhere. I can't really tell were it is coming from.

This vehicle had an alternator installed by someone that was also underneath it when doing the installation. I am not sure if he may have put a hole in it or if the fitting has come loose. I can, t see all of the line from underneath the truck.