I JB "Welded" a steel washer in the aluminum pan on the transmission in my 04 Mercury Marauder 3 years ago!!
It holds the magnet it place that catches any ferrous metal debris and so far it has held up well....180*-200* constantly immersed in ATF!!
Surfaces MUST be clean as mentioned before...I'd go for it!!
BTW, it is supposed to be good to 600*F and your lifter valley should never see more than about 200*??
