8.2 rear contact pattern
 

1st time setting one up. Original 3.23 GM gear on Auburn limited slip. Coated teeth but cannot see the contact pattern clearly on the coated teeth. The grease transfers to the other teeth and it LOOKS like I need to move closer to center on both drive and coast side. I would like a more experienced opinion and an idea why it is not showing up clearly on the coated teeth. See attached pics.

Couple more pictures. It's probably something basic I am missing....

You need to "load" the axle when you check the pattern...hold your hand on the axle while turning the pinion and you'll be able to see it better. If it stays like your picture, you may need to shift the carrier to get better contact. What's your backlash number look like?

Much better. Backlash was on the high side at 0.009"

I still don't think you are loading it enough. the way i do it is holding the pinion yoke with a glove and turn the carrier with a wrench. the most inportant pattern is on the drive side with new gears. with used gears you still want to look at driveside, but coast side will give you better information.

backlash should be 6-12 with 5 cut gears. 3 cut gears will be on the lower side 2-6? Pinion torque should be around 25 inch pounds rotating with new bearings. with used bearings around 10-15 inch. it's better to have to have a little to much preload then not enough.

you can't get a good pattern reading unless backlash and nut preload are set correctly.

Used gears and used pinion bearings. Preload is 17 lbf-in

Slight improvement in clarity using wrench to turn carrier while loading axle.

going by the chart, you may need a thicker shim behind the pinion. I would only add about 2-3 thou and check again.

I still don't think you can tell much from the current pattern. You need more load on the unit to get a clean pattern. From the little I can see, you may be OK. The pattern will move back toward the heel of the tooth as the load increases. I generally use a long ratchet or breaker bar to turn the pinion and wedge a pry bar between the housing and the outside of the ring gear to get significant load against the ring making it hard to turn. It should take a minimum of 50 ft. lbs to keep the pinion turning when doing a pattern check.

Thanks all. Had to stop for the day. Will apply more load and check again.