To check the gear tooth pattern, paint several ring gear
teeth with nondrying Prussian blue, ferric oxide, or red
or white lead marking compound. White marking compound
is preferred by many technicians.because it tends
to be more visible than the others are. Use the pinion gear
yoke or companion flange to rotate the ring gear. This will
preload the ring gear while it is rotating and will simulate vehicle load. Rotate the ring gear so the painted
teeth contact the pinion gear. Move it in both directions enough to get a clearly defined pattern. Examine the pattern
on the ring gear and make the necessary corrections.