First are you sure that it's tranny fluid and not engine oil? The JK's oil pan is notorious for leaking in that spot right above the large adapter plate between the transmission and the oil pan. If it's the oil pan gasket, it's a cheap repair that can be done during your next oil change.
The transmission pan is farther back and it would be obvious if it were leaking. If it's transmission fluid and leaking in that spot, then you have a larger and more expensive problem. A transmission leak in that spot indicates that the front pump seal has failed which requires the complete removal of the transmission (along with your driveshafts and transfer case). If it is the seal, many will opt for a complete transmission rebuild because the mechanic will already have the transmission removed and partially disassembled.