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Technical 62 Impala differential setup

Discussion in 'The Hokey Ass Message Board' started by RPM1960, Apr 23, 2019.

  1. RPM1960
    Joined: Apr 23, 2019
    Posts: 9

    RPM1960

    I've got a 62 Impala I've replaced the ring/pinion gears and I'm having a tough time getting the right pinion shim setup.
    It has new bearings and a different used ring/pinion then it originally had and the stock shim was a 26 thousandths. I noticed the shim was worn on the outer diameter and measured about 23 thousandths but I put in a 26 like the original was. After slathering them up with gear marking compound I take a look and compare it to the charts and it shows what I believe is pinion is too close.
    Can anyone look at these pics and tell me what it means?

    Robert
     

    Attached Files:

  2. fastcar1953
    Joined: Oct 23, 2009
    Posts: 3,567

    fastcar1953
    Member

    this might help. Figure_28.jpg
     
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  3. Budget36
    Joined: Nov 29, 2014
    Posts: 13,174

    Budget36
    Member

    Seems you're a bit too far away
     
  4. RPM1960
    Joined: Apr 23, 2019
    Posts: 9

    RPM1960

    DSCF7433.JPG
    OK, I changed out the shim to an .030 with .008 backlash and this is what I got.
    I rechecked the original shims, and the one that came with this pinion was an .030 so I assume I'm in the ballpark? DSCF7423.JPG
     

  5. mohead1
    Joined: Jan 18, 2013
    Posts: 599

    mohead1
    Member

    Not distinct enough of a pattern....butter them up again and run it...you got em smeared around now

    Sent from my SM-G900V using Tapatalk
     
  6. RPM1960
    Joined: Apr 23, 2019
    Posts: 9

    RPM1960

    Yeah, I ran out of gear marking compound and even though I turned the gears at least 20 times I couldn't get a clean pattern on the coast side. I'll have to try again when I get some more compound. I have some prussian blue, but I've heard it won't work well for gear meshing.
     
  7. mohead1
    Joined: Jan 18, 2013
    Posts: 599

    mohead1
    Member

    Light coat of prussian may work but man that shit will get on everything....most larger auto parts places will have some gear marking compound

    Sent from my SM-G900V using Tapatalk
     
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  8. buffaloracer
    Joined: Aug 22, 2004
    Posts: 816

    buffaloracer
    Member
    from kansas

    Hard to tell by looking at photos but your original photos looked pretty good to me.
    Pete
     
  9. You have to put some load on it to get a clearer pattern, I wrap a rag around the pinion to add some resistance to turning it.


    Sent from my iPhone using H.A.M.B.
     
  10. RPM1960
    Joined: Apr 23, 2019
    Posts: 9

    RPM1960

    OK, here's another try with the gear marking compound.
    55P carrier
    BL=.008
    PL=12 in. lb.
    Pinion shim=.030

    DSCF7446.JPG
     

    Attached Files:

  11. mohead1
    Joined: Jan 18, 2013
    Posts: 599

    mohead1
    Member

    Not good

    Sent from my SM-G900V using Tapatalk
     
  12. RPM1960
    Joined: Apr 23, 2019
    Posts: 9

    RPM1960

    Yeah, I think I'm going to have to clean it all up and start over.
     
  13. mohead1
    Joined: Jan 18, 2013
    Posts: 599

    mohead1
    Member

    Yep

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  14. Pinion is too far in


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    gimpyshotrods likes this.
  15. Theres a guy on utube who is a shop teacher who did a rebuild how to on this center section.I believe its rebuild a 63 belair rearend.He is very good ,and goes in to detail how to get the correct pattern on the teeth.
     
  16. big duece
    Joined: Jul 28, 2008
    Posts: 6,830

    big duece
    Member
    from kansas

    I would pay more attention to the drive side instead of the coast side. If you have the old pinion bearing and its not shot, take and flap disk the ID and use it to slide on and off by hand when your swaping shims out like this. Or, sacrifice a new bearing. The first pattern looked pretty good from the pics at .026 shim. For giggles, thrown in a .023 or .024 and see where the pattern goes.
     
    Deuces likes this.
  17. RPM1960
    Joined: Apr 23, 2019
    Posts: 9

    RPM1960

    I think I saw that video. There was a 4 part video by a guy in a wheelchair that goes through teardown and reassembly, but his was pinion spot on when he checked it, so there was no diagnosis on how to do any corrections.

    I've gone through shimming my pinion from .025 to .030 and saw some changes, but I'm having a hard discerning the patterns I'm getting. Last time I think I got some oil on the pinion which would explain the messy pattern. I'm going to clean it all up and start over.
     
  18. big duece
    Joined: Jul 28, 2008
    Posts: 6,830

    big duece
    Member
    from kansas

    Just mark about 5-8 teeth, no need to see the pattern all the way around the ring gear.
     
  19. 427 sleeper
    Joined: Mar 8, 2017
    Posts: 2,872

    427 sleeper
    ALLIANCE MEMBER

    It has been my experience that the shim that the factory installed with the housing is what you should use, provided you are replacing a factory gear with another factory gear. Aftermarket gears will require a depth verification.
     
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  20. saltflats
    Joined: Aug 14, 2007
    Posts: 12,594

    saltflats
    Member
    from Missouri

    How much load do you have on the ring and pinion when your checking the pattern?
     
    427 sleeper likes this.
  21. We were taught to grab the ring and turn the pinion with the ring, this will produce the easiest to read pattern.


    Sent from my iPhone using The H.A.M.B. mobile app
     
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  22. RPM1960
    Joined: Apr 23, 2019
    Posts: 9

    RPM1960

    I'll get back to the differential in a few days. Too many other things to repair on the car for now.
    It's been a project car (1962 Biscayne Wagon) that I inherited from my father that ended up need much more work then I first though it would. My dad bought this car brand new when I was 2 years old, so I've always been familiar with it and what's been repaired on it over the years, but lost track once I got married and and kids... and such.
    Dad past away last year and when I got the car it was mechanically a mess. He had it painted and fixed up the bodywork, so it looks great, but the mechanicals are in need of repairs.
    Fast forward to now, the differential has been leaking for several years and dad always thought it was just a bad gasket, but once I got the car to my place it turns out to be much worse. The yoke nut came off way too easy and when I pulled the differential it apparently had been loose for some time. It seems that dad at some time may have pulled the yoke off to replace the seal thinking it would fix the leak and just bolted the yoke back on with no new preload bushing.

    Fast forward to now.... the pinion gear had chewed into the carrier some, and the ring gear looked mottled on the surface, so they had to go. New bearings and a good used gearset and here I am... trying to get it set up.
     

    Attached Files:

    Last edited: Apr 26, 2019
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  23. saltflats
    Joined: Aug 14, 2007
    Posts: 12,594

    saltflats
    Member
    from Missouri

    Being a used set of gears, you may want to try setting it up with more backlash.
     
  24. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,214

    sunbeam
    Member

    I would start with the shim pack from the orginal pinion. And as saltflats said open up the back lash a couple of thousands on used gears.
     
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  25. RPM1960
    Joined: Apr 23, 2019
    Posts: 9

    RPM1960

    OK, went to the original shim size of .027 backlash=.010 Still not getting a clear pattern.... I'm not sure what I'm doing wrong. Too much compound... or to little? I'm turning the ring gear while holding a bit of pressure on the yoke with a rag.
     

    Attached Files:

  26. big duece
    Joined: Jul 28, 2008
    Posts: 6,830

    big duece
    Member
    from kansas

    So far, the first pattern looks the best

    Sent from my SM-G900P using The H.A.M.B. mobile app
     
  27. 427 sleeper
    Joined: Mar 8, 2017
    Posts: 2,872

    427 sleeper
    ALLIANCE MEMBER

    Sometimes less is more when it comes to marking compound. That being said, clean it off and try it again. But, from what I can make out, if you run it the way it is right now you'd probably be happy with what you have. JMO.
     
    jimmy six likes this.
  28. Yeah..Just might make a bit of noise on coast. Then again, it might anyway, with used gears.
    My experience is that is you take a used set that's worn to .011-.012 b/l, and re-install at .006-.007, it's likely to make noise anyway. Might never get the pattern perfect either.
     
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  29. mohead1
    Joined: Jan 18, 2013
    Posts: 599

    mohead1
    Member

    Youre good, run it

    Sent from my SM-G900V using Tapatalk
     
  30. Deuces
    Joined: Nov 3, 2009
    Posts: 23,753

    Deuces

    That's what I had in mind....
     

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