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Discussion Starter #1
Hey Guys, I have been chasing my tail on this and it is driving me insane.
This is my daily driver, so I need to get it back up and running ASAP, and I dont really have the option to run it, and rip it all apart again...

I have a 7.625 diff, with 3.08 STOCK gears, open carrier that I am setting up out of my 4.3L 5 speed.

My pinion shim is slightly larger (.003") than the stock one I pulled out, and my initial backlash comes out exactly where I want it (.008" when the spec I found says .006-.010") which is perfect for the manual.

This makes my pattern favor the root of teeth, but nothing too huge.
When I go to shim the carrier left & right, I can center my drive nicely between the toe/heel but my coast is consistently towards the toe.

Let me know what you guys think of my contact pattern. I have took this thing apart almost 5 times already, and im starting to worry about my destroying my pinion bearing. I have already crushed my crush sleeve thinking my last attempt was my final attempt, so I have been setting my pinion preload to the 6-12 in lb spec for a used sleeve.

Im ready to say Fak it, and run them. See if they whine or not. Please let me know what you guys think based on your experiences
 

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Looks to me like the pinion is too deep. I'd take about .003 out of the pinion shim and try again. With a used gear you need to look more at the coast pattern than the drive pattern because the coast pattern will have much less wear on it, and the pattern will be more accurate. Most of the time a used gear will not give any kind of a readable pattern on the drive side.
 

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Discussion Starter #3
Thanks for the reply!

My only concern with reducing my pinion shim is when I pull that .003" out, my backlash comes out of spec at .011". Will I be able to bring this back to a correct value by shimming left right?

And I never considered the uneven wear of the gears. This is a great point!
 

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Awesome, thanks for the advice! I will rip it apart and try to alittle shallower, and see if I can hit my specs.
Will let you know how it turns out
 

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Discussion Starter #7
Sorry about the delay, I was moving all weekend.
I went through a few iterations yesterday and ultimately settled on a pattern

- I pull .003" out of the shim, and this centered the pattern on the tooth as best as it would get.
- Pulling more out shifted it too closely to the top of the tooth
- PROTIP: Since it was alittle difficult to actually tell where the centerline of the tooth was,
We stretched a piece of string from the front center to the rear center of the tooth
and it shows you exactly where center is, so you can see where your contact is!!
- my final contact LOOKS alittle deep, but when we checked this, is was actually fairly centered

- Total runout on the ring was .0025"... reasonable, but also showed me where I needed to double check
backlash in a few different areas

- First two pics, my contact pattern looked good, but after double checking, my backlash was too tight (.005-.007")

- The last two pics: I opened this up to an almost ideal .007-.009 which I am rather happy with, since it is a manual

- Upon the above advice, I focused more on the coast side since they are stock gears, and actually came out with one
of the best coast patterns I have had yet (sorry about the pictures, I forgot to take some the first time, and had little load the second)

- The drive is favoring the toe alittle, but this would be predicted due to the tooth wear.

- My only remaining concern is that the patern on the pinion was from the centerline to the edge, and not nearly as nice as the ring
- Should I be concerned?
- Any more feedback on the contact would be awesome!!!

Thanks for the feedback and help
 

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It's a little hard to see. It looks like the pinion might be a little too deep in the first picture. I can't see it very well in the third picture, but it looks like it might be a little better. Have you done the final assembly on it yet?
 

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Discussion Starter #9
Yeah, it was alittle deep on the first, and came out alittle better on the third.

I have done the final assembly and mesh (that is pics 3&4) and it's ready to be filled and installed.
I have been waiting to see what you guys have to say.

And final tips before I run them?
 

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Did you use red Locktite on the pinion nut on the final assembly? If you got the bearing preload set right then it should be ready to go.
 
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