Could someone please explain to a dummy what the yellow stuff is, the significance of the meshing marks, and why the concensus is to send it out as is? TIA.
It's just an oil based yellow paint. You want the meshing pattern more-or-less centered on the ring gear teeth, but it's better to have on the inside (smaller, inner radius) because under load, the small deformations and forces push the pattern outward (towards the outer diameter.)
You also want the marking pattern centered, depth-wise. Too close down to the heel of the ring gear I think generates too much friction, and too far out can cause the teeth to break off since only the points of the teeth mesh and transfer load. These a general guidelines, of course.
That's from my recollection of me watching YT videos on the subject...and regearing an axle in my garage.
