Looking for confirmation on my ring gear pattern marking

[jneely]

I am installing a new Richmond 3.70:1 gear set and Yukon Trac-Loc in the 9 inch for my '68.

I'm new to gear set, so am looking for some input on the marking pattern I'm seeing. Backlash is mid-spec at 0.008". The original pinion carrier shim was 0.018", and I've tried everywhere from 0.014 to 0.024", and it all looks about the same on the drive side. Coast pattern looks a bit wider and more centered on the lesser shim thickness. The pattern looks more like a parallelogram than an oval to me, but it's good and wide and relatively centered. Any concerns to run with this pattern?

Any help appreciated. Thanks in advance.

[66f250cs]

I am not a differential expert. I looked in my Ford shop manual, General Axle Service, "Tooth contact pattern check" and am quoting from the manual based on your pics: Drive side - desirable pattern - correct shim, correct backlash - coast side. (Sorry I can't send you a scan of the manual). Looks like what you have matches the drawings in my shop manual. The other eight scenarios, four drive and four coast show contact patches at the ends of the teeth or towards the tops of the teeth. Your pics match the shop manual the closest for desirability.

[Ranchero50]

Looks pretty good. Not in the valley or riding the peak, centered over the span. Lash is always very subjective and running it too tight is the easiest way to create whiny gears. I'm typically happy with less than 1/16" (.030-.050") rotation of the pinion gear at its seal diameter. You want a little movement, not a solid lockup between drive and coast. Checking used gear sets in the 4.10 range it's not unusual to get 1/8" or larger rotation of the pinion.

[jneely]

Ok, thank you. I will consider this good and proceed with final assembly.

Any tips on an easy way to remove the marking compound? I don't want to spray brake clraner everywhere for fear of washing off bearing prelube. Better yet, can it be left on?

[Ranchero50]

I'd just ignore it. Used car salesmen used to put saw dust in rears to quiet them down so I don't think a little marking compound is going to hurt.