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Technical Mopar 8 3/4 used rear swap

Discussion in 'The Hokey Ass Message Board' started by zep058, May 30, 2014.

  1. zep058
    Joined: Jan 9, 2007
    Posts: 599

    zep058
    Member

    So I've been wanting to change from my 2.76 highway gears for a while now and managed to pick up a complete axle with 3.23 gears cheapish.
    Had been sitting covered for a few years with oil in it (or should I say brown ooz).
    Overall it seems pretty good, no bad wear patterns or clunks etc. and wondering whether to give it a good clean and throw it in to my case and run it.

    What would you do and what are some checks I can do without a full tear down and rebuild which funds won't allow. Am I crazy thinking I can just bang an unknown rear in?!

    Thoughts?




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  2. saltflats
    Joined: Aug 14, 2007
    Posts: 9,784

    saltflats
    Member
    from Missouri

    I would clean it up and just turning it buy had you should be able to tell if it turns smooth or not if it truns smooth I would stab it in.
     
  3. 69fury
    Joined: Feb 24, 2009
    Posts: 1,416

    69fury
    Member

    Agreed- if there's no signs of metal in the oil, then just clean it and chuck it in with new lube. They're pretty indestructable in a stock car, so i doubt it's got issues if you dont see any glitter in the oil.
     
  4. GTS225
    Joined: Jul 2, 2006
    Posts: 1,136

    GTS225
    Member

    A; Is it a Sure-grip?
    B; If so, is it a clutch-type, or cone-type?
    C; If cone-type, check out the cones. They could be worn to the point of non-functional.

    Roger
     
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  5. 49ratfink
    Joined: Feb 8, 2004
    Posts: 17,548

    49ratfink
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    from California

    I think you should ship it to me so I can get rid of my hiway gears in my 61 Dodge.
     
  6. saltflats
    Joined: Aug 14, 2007
    Posts: 9,784

    saltflats
    Member
    from Missouri

    49ratfink what gears you looking for and for what housing?
     
  7. need louvers ?
    Joined: Nov 20, 2008
    Posts: 12,911

    need louvers ?
    Member

    I too fall into the "just throw it in and run it group. Matter of fact, I did the exact same gig with my Plymouth about 100,000 miles ago. GTS 225 does bring up a good point though. If it is a cone type sure grip, those do wear to the point that the cones contact the out edges of the cases. I followed an article I Mopar Muscle from about ten years ago by Steve Dulcich on rebuilding then by machining the cones and re-shimming. It has worked very well ever since, so if you DO have problems, there is hope.
     
  8. zep058
    Joined: Jan 9, 2007
    Posts: 599

    zep058
    Member

    So the "throw it in and run it" wins! I'm that way inclined just to give it a go.

    No metal and turns over by hand with no audible issues.

    I wish it was a sure grip! If I like this ratio I may throw a tru trac at it but for the moment just want to see what the gear change offers.
    I don't have another gasket but read to use a bit of rtv or sealant as an easy fix. Hopefully it seals it up no problem.

    Thanks for the advice gents
     
  9. 50dodge4x4
    Joined: Aug 7, 2004
    Posts: 3,536

    50dodge4x4
    Member

    I haven't used a real gasket for a Mopar rear axle cover or center section since the mid 70s. Give the rtv time to set up before you fill it with gear lube and your good to go.
     
  10. 270dodge
    Joined: Feb 11, 2012
    Posts: 696

    270dodge
    Member
    from Ohio

    So is it a 471-472 or a 489? If it is a 489 I can help (oh my, shipping !). Yes go for it.
     
  11. zep058
    Joined: Jan 9, 2007
    Posts: 599

    zep058
    Member

  12. zep058
    Joined: Jan 9, 2007
    Posts: 599

    zep058
    Member

    Yes 489.

    I wanted to show a video of the spider gears as they have some movement in them, not sure if the tolerance is okay

    ImageUploadedByH.A.M.B.1401515606.141883.jpg

    ImageUploadedByH.A.M.B.1401515642.069108.jpg

    Here a snapshot to show the gap, hope that makes sense


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  13. zep058
    Joined: Jan 9, 2007
    Posts: 599

    zep058
    Member



    try this
     
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  14. zep058
    Joined: Jan 9, 2007
    Posts: 599

    zep058
    Member

    Last one then I'm done



    So from the videos, is that much movement acceptable? This is my first with a mopar rear end so not sure if it's okay to run.

    Thanks for listening!
     
  15. saltflats
    Joined: Aug 14, 2007
    Posts: 9,784

    saltflats
    Member
    from Missouri

    The back lash on the pinion looks OK but the side gear movement dont look good.The carrier may be shot but you may be able to save it with some more shim behind the side gears.
    If you take the carrier out I would check the back lash with a dial indicator and make sure you set it up with the same reading.
     
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  16. daliant
    Joined: Nov 25, 2009
    Posts: 683

    daliant
    Member

    That's a lot of play on the spider gears, I would pull 'em out and shim them up nice and tight. Someone probably did a lot of peg-leg burnouts with that thing.
     
    zep058 likes this.
  17. Heads up.... The ring gear attachment bolts are left hand thread.... Ask me how I know.
     
  18. zep058
    Joined: Jan 9, 2007
    Posts: 599

    zep058
    Member

    Thanks saltflats, it's starting to look like I should do this properly and get a rebuild kit and invest in a dial indicator. When you say set the backlash is that axle adjuster?

    Daliant, you are correct, evidenced by the bald tyre on the peg leg. Was hoping to just swap and go but may have to reconsider


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  19. saltflats
    Joined: Aug 14, 2007
    Posts: 9,784

    saltflats
    Member
    from Missouri

    The backlash is the clearance between the ring gear and the pinion. If I reuse a ring and pinion set I like to reset the backlash as it was you stand a better chance of not having a noisy gear.
    The adjuster behind the axle flange is for adjusting the axle bearing free play.
     
  20. daliant
    Joined: Nov 25, 2009
    Posts: 683

    daliant
    Member

    Now's a good time to put a sure grip in it or one of those quick lockers that replace the spider gears on an open diff.
     

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