If you use it, be sure to wrap it with the thread so it doesnt fall off inside the joint. Also, dont apply it to the first two threads to guard against this. I dunno what PTFE tape would do to a transmission, specially if it got in after the filter. . *shudder*
I`d recommend using a light coat of grey pipe dope with teflon in it, its the most non-reactive type. Compression or thread fittings, use sealant. Flare or o-ring, just use a small amount on the threads to lube em up. (lil bit on the back of the flare helps to lube it also)
good luck
-j