2001 Lexus IS 300 transmission fluid leak

My Lexus IS300 the transmission fluid is leaking underneath the transmission pan. I went to PEPBOY to get a check up. The mechanic person told me that the transmission line fitting was where it leak. They unable to help me with that situation, but told me to go to a transmission shop or to LEXUS dealer. Is there a way that i could fix the problem by myself?. Or can I use a sealing silicone from AUTOZONE, PEPBOYS, or any other parts store to seal that leaking?. Please let me know. I would be more than happy to appreciate you.