Black Oxide on Bolts

[odcics2]

When is Black not black!


"Black Oxide versus Black Phosphate. ... A. David - Yes, black oxide can be used as a rust retardant, but it is not as effective as black phosphate. The black zinc phosphate acts sacrificially to protect the steel, whereas the black oxide will rely on the after-finish for corrosion protection."

As stated above, Chrysler used black phosphate.  My bellhousing to engine, trans to bellhousing, oil pan, clutch pressure plate, trans crossmember, and the torsion bar anchor on the pass side are a few of the places my car has them.