coolant/tranny fluid leak

[bigblue41]

So I noticed today that I have a leak coming from what appears to be my new radiator from 1800radiator. Had it for about 3 months. However I am using CAT ELC and cant distinguish whether or not it is just coolant, tranny fluid, or both. The entire bottom of my radiator was filled up earlier to where it was on my leaf springs. I dipped a towel in it, and it had a slight greasy feel to it similar to tranny fluid, however upon smelling it, I could not pinpoint it at all, then my sprinklers cut on and the evvidence on the ground was washed away completely. truck must be running to check tranny fluid level, right? I checked my coolant level and it was below the min mark however it is usually under it. Any advice/ideas/things to check for elimination would be great. Thanks in advance for the help and all the kickass help Ive gotten from everyone before.