Trans Drain Plug Struck

Aybody ever have trouble getting the drain plug out of a 5 speed trans? It's in a 99 Sentra and I wanted to put BG syncroshift in it. The drain plug won't budge despite using a proper 13mm male drain plug socket and a 25" breaker bar. Since getting enough leverage on it from underneath is awkward, I ran a couple of long 1/2" extension bars out of the drain plug socket so that the long breaker bar can be worked while standing up next to the left front wheel well. Still won't budge. Feels like either something will break (I've already wrung the short square end off of a 24" long 3/8" extension bar!) or just mangle the drain plug square indent if I put more torque on it. I suspect that the problem is likely the sealant that Nissan uses on the plug. Getting the filler drain plug off was a bear too and it had a lot of sealant on it. I'm not sure heat will help if the sealant is the problem. Has anybody else had this problem and solved it? Thanks in advance. Al