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9 inch pattern help

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Old Oct 13, 2017 | 10:48 AM
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Default 9 inch pattern help

Backlash is .08, .017 shim on the pinion. Where should I go from here? Losing patience. I just want them to be QUIET. They are U.S. Strange 4.10s.
any help/advice is greatly appreciated.

Jon
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Old Oct 13, 2017 | 12:19 PM
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From: Turnin' Wrenches Infractions: 005
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The pinion shim spaces it away from the ring gear right (on a 9 inch)? Add some shim to get the gears to move apart. You can tell bc of the hard line at the bottom of the tooth on the second pic. They are meshing too far into each other.
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Old Oct 13, 2017 | 12:20 PM
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From: Turnin' Wrenches Infractions: 005
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I would try a 20-22 and see how the pattern looks, you arent far, dont get discouraged. PM for faster response if you have specific questions.
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Old Oct 13, 2017 | 01:02 PM
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Old Oct 13, 2017 | 01:04 PM
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That looks a ton better
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Old Oct 13, 2017 | 01:05 PM
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I think i would take it out a smidge more and see if that coast will center up
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Old Oct 24, 2017 | 12:47 AM
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Your right it does look better but it kinda looks like the depth is starting to come up a bit high on the face and putting a thicker shim in there will move it even higher on the face I would try to move the pinion in deeper to get the pattern back down deeper towards the flank of the tooth and then increase the backlash to keep the pattern kind of in the center between the toe & the heel.
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Old Nov 6, 2017 | 07:37 AM
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I didn't go with the pattern posted, and I guess I deleted the pics of what I went with. Break in miles are done and its good and quiet. Time to change the fluid and let it EAT!
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Old Nov 6, 2017 | 07:44 AM
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Good deal........
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Old Nov 6, 2017 | 07:23 PM
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Default 9" pattern

It' opposite to what you would think. To move the pattern deeper or shallower into the valley of the tooth you move the pinion. To move it up or down from heel to toe ( like you need to ) you move the ring gear sideways with the threaded adj rings. Yours is bad. I just did one with a pattern exactly like yours on a 10blt. ( all diffs take the same adjustments to move the pattern ) I moved the ring gear away from the pinion .015 and the pattern was great and the noise went away. Sometimes it gets tricky when you have such a sharp edge on your pattern but just go with increasing your backlash like i said and see what happens. Don't get to concerned about going over 10 or 12 thow back lash. I've had to go 15 even 20 thow on some used gear sets to get the pattern right. Thats the important part, the pattern. Bottom line, doesn't matter the final measurements if the pattern is correct. Is your gear set used? How many miles were put on it while it was making noise? It could develop a bad ware spot on the tooth ( bad pattern worn right into tooth surface ) that you cant get rid of. If to many miles were put on it it might make noise forever. ( fingers crossed) do the teeth have a burr on the bottom edge from one gear running onto the edge of the other. That's not good but might be ok. Try the adjustment and do another pattern check and we'll go from there
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Old Nov 6, 2017 | 07:28 PM
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Originally Posted by 01ssreda4
The pinion shim spaces it away from the ring gear right (on a 9 inch)? Add some shim to get the gears to move apart. You can tell bc of the hard line at the bottom of the tooth on the second pic. They are meshing too far into each other.
you need more backlash, not less pinion depth
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Old Nov 8, 2017 | 08:16 AM
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If you say so. Ive never setup a set that was 15-20 backlash, that's ridiculous and too sloppy for my tastes.
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Old Nov 8, 2017 | 09:01 PM
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Default 9 inch pattern

Originally Posted by 01ssreda4
If you say so. Ive never setup a set that was 15-20 backlash, that's ridiculous and too sloppy for my tastes.
haha, ya me two, of course you would never intentionally set a diff up with that much back lash...... if you can help it. I was just referring to the extremes I've had to deal with when working on some used crap thats already been howling. I' sorry if I've offended anyone. I was worried about anyone thinking I was stepping on someone's territory. I really was just trying to help. I actually do have alot of experience. I've been a licensed mechanic for about 35 yrs and have done probably 100s of diffs with great success. I'm new here so maybe I'll just hang back and watch for awhile. Once again sorry about that
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Old Nov 9, 2017 | 07:43 AM
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I try to never use or setup used gears, so my experience there is limited. Ive had plenty of offers to do gear swaps and if they wont bring me new gears, I simply wont do the job for them and tell them to walk. I dont want the headache.
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Old Nov 9, 2017 | 04:10 PM
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Originally Posted by 01ssreda4
I try to never use or setup used gears, so my experience there is limited. Ive had plenty of offers to do gear swaps and if they wont bring me new gears, I simply wont do the job for them and tell them to walk. I dont want the headache.
Do you prefer 5 or 2 cut? I think working with a 6-10 bl is way more sane than trying to keep a 3-6.
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Old Nov 9, 2017 | 09:07 PM
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I haven't kept up with who makes what cut. I've had good luck with motives. The blue box gears are great for the new guy trying to setup a quiet rearend.
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Old Nov 10, 2017 | 10:45 AM
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Originally Posted by 01ssreda4
If you say so. Ive never setup a set that was 15-20 backlash, that's ridiculous and too sloppy for my tastes.
Agreed. That's bogus and gonna be a slop monster. Even used gear installs are not set that loose.
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Old Nov 10, 2017 | 10:48 AM
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Originally Posted by 01ssreda4
I try to never use or setup used gears, so my experience there is limited. Ive had plenty of offers to do gear swaps and if they wont bring me new gears, I simply wont do the job for them and tell them to walk. I dont want the headache.
Used gear Install can be tricky. It's an art for sure. It took me lots of training and practice to get it right. You definitely have it easier with new as you said.
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Old Nov 10, 2017 | 12:29 PM
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Anything over .008 will be sloppy and cause a nice CLANK when engaging into gear. When using used gears I've found using a heavier gear oil helps lower the whine and if its a 10bolt in a Camaro-Firebird you're going to experience some whine from 40-70 mph no matter what you do. Setting the backlash at .015 is crazy in my book. I worked on a TA that the dealer setup @.012 and it was terrible, noisy loose sloppy.
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Old Nov 10, 2017 | 01:31 PM
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From: Turnin' Wrenches Infractions: 005
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Add in a body mounted torque arm and you feel and hear everything inside the rearend.
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