Rear diff shim after shackle flip?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Thumper, Oct 16, 2001.

  1. Thumper

    Thumper 1/2 ton status

    Feb 17, 2000
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    Alberta Canada
    I have had the shackle flip done for a month or so, but went for the first real hiway run today. I have a driveline vibe, around 80 Km/h on the way up and the way down. I know the angle isnt quite right. When I did the flip, I added a shim, I think its 3 or 4 deg, but apparently not enuff. How much did everyone else have to shim it down to get the right angle? I will get it manufactured into a 1" lift block.


    <font color=blue>Thumper
    85 Fullsize Jimmy
    <font color=red>Aint Skeered!! </font color=red>
  2. zakk

    zakk 1/2 ton status

    Sep 21, 2001
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    San Jose CA
    you will need to measure the degree diff between the diff and the t-case. there is a much more scientific explanation of what to check but i don't know/ understand it [​IMG]
    there is no cure all. it will depend on a ton of different variables.

    '77 K5 SB 400 TH350 NP203 p/t 6" Lift D60 14BFF 4.10's 36"Wrangler II's

    [​IMG] CK5's MOAB 2002 OR BUST!! [​IMG]
  3. K5RON

    K5RON 1/2 ton status

    Apr 14, 2001
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    If running a cv driveshaft, the angle between the driveshaft and the diff yoke must be O* meaning that the diff yoke must point directly at the output shaft of the xfer case.

    If running a non-cv joint driveshaft, the angle of the driveshaft coming out of the xfer case must be equal to the angle at the pinion yoke.

    I use a cheapo protractor from Sears with excellent results. The degree shim(amount of) has to do with the amount of lift, most applications are different!

    With my 2 1/2" shackle flip and a 14BFF plus a cv shaft, I use no shim! I do have a slight vibe at about 80-90MPH but I don't ever go that fast as the 1-1 ratio of the SM465 doesn't allow me to!


    '84 K5......Tree Fitty, SM465/Np205, D44/14BFF, Pro-jection! .....and of coarse no other color than Odie!

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