8.5 rebuild and upgrade. Advice and guidance needed

Discussion in 'Transmission & Driveline Topics' started by Camaromurph, May 17, 2020.

  1. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    definitely OUT of the car. You can make a yoke holder out of MOST anything....and a drill bit. ;)

    [​IMG] upload_2020-5-20_8-8-24.jpeg
     
  2. Bandit723

    Bandit723 Veteran Member

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  3. Camaromurph

    Camaromurph Veteran Member

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    I’m going to start reassembly this weekend. Thoughts on using the crush sleeve during initial set up? Is it okay not to use it?
     
  4. big gear head

    big gear head Veteran Member

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    Do not install the crush spacer until the final assembly. Use the old nut for trial assemblies and save the new nut for the final assembly. Be sure that you set the pinion bearing preload correctly for every trial assembly. Use an axle to turn everything when checking the pattern. Turn it about 6 full turns in both directions.
     
  5. Camaromurph

    Camaromurph Veteran Member

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    So good day today.

    Installed the pinion bearing races and the axle bearings.

    Got the pinion shims on and the inner bearing pressed on. I didn't have a 0.001" feeler gauge to check but I did have a 0.002" gauge. I was using a press so I'm pretty sure they went on all the way.

    Pressed the bearings on the Detroit Truetrac. Then proceeded to try to find the perfect slip fit for the carrier shims. I started with the old shim dimensions and subtracted about 0.004" from both. I could not get the shims in easily so I took the smallest shim out and it slide in. I set up a dial indicator to check for side to side movement. My first try their was about 0.001" movement so I changed up a shim and got it to virtually nothing. This is what I will start my set up with. I did not put the bearing caps on when I did this. I hope this was Okay.

    I then got the ring gear mounted to the Truetrac and torqued down.

    It was nice having my helper for the day. Tomorrow will be back under the car cleaning off undercoating and on Monday when I get my helper back we will start installing the pinion and gears and checking the pattern.
     

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    dave@ztech and big gear head like this.
  6. biker

    biker Veteran Member

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    Nice work! great benefit to your helper to go through all this as well.
     
  7. Camaromurph

    Camaromurph Veteran Member

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    Okay, quick question. I set the pinion bearing preload for my first trial run. My Chevy factor repair manual calls for 24-32 in-lbs for new bearings where everything else seems to indicate about 18 in-lbs. right now I have it set at about 27.5 in-lbs. Is that okay?
     
  8. camaro71/holland

    camaro71/holland Veteran Member

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    A bit on the high side, but it would live. I aim for 22 - 25 preload. Make sure you set the same preload on every attempt till you're done.
     
  9. Fbird

    Fbird Veteran Member Lifetime Gold Member

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    believe most stuff has been covered... only other thing i could recommend is when setting your backlash.....take note of the indicator TRAVEL direction. (hard to put into words) You want the indicator to travel in a straight line with the gear tooth....not some obscure angle..

    upload_2020-5-26_6-21-52.jpeg

    see how the TRAVEL of the indicator will make a small CHORD relative to the CIRCLE of the ring gear...also note you are only traveling about .020 ....but consistency in your set-up will allow you to compare APPLES to APPLES when making shim changes.

    also when post pics of your pattern for ?'s.....it is better to view when the pic is perpendicular to the FACE of the tooth... like this
    [​IMG]

    as opposed to this
    [​IMG]
     
    Last edited: May 26, 2020 at 6:29 AM
  10. big gear head

    big gear head Veteran Member

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    That's too much bearing preload. You should be around 20-21 inch pounds.
     

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