I put a NAPA Drain Plug on my transmission pan, I went ahead and got a copper washer. The bolt that goes into the pan has a slight leak, there is always a dab on the bolt. I tried tightening the bolt, but I have the same problem. Do I need to take the bolt out and use some of that liquid lock thread stuff, I am thinking the trans fluid is getting past the bolt threads somehow and if I put some lock thread on it will seal the thread and no more leak. Let me know what you guys think, because if this does not work, then I will have to spend $75.00 for a pan with a drain plug already in it. Yes, the nuts on each side of the pan are very tight. Any advice would be appreciated.