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Help! Shackles installed...but no instructions for pinion shims!

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Old Jun 29, 2011 | 06:26 PM
  #11  
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[QUOTE=Coban;4725904]Help! Shackles installed...but no instructions for pinion shims!-yweam.jpg[/QUOT

Cool picture......
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Old Jun 29, 2011 | 08:48 PM
  #12  
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Pinion angle should be -3 to -4 degrees. Nevermind what it was stock, and shoot for that.
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Old Jun 30, 2011 | 12:45 PM
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This has been driving me crazy, but I've found my answer:

From 2006:
https://www.performancetrucks.net/fo...d.php?t=373595

http://www.stylintrucks.com/articles...ion_shims.aspx

These ^^^ confirmed what you guys have been telling me. Perhaps the most helpful info so far (from Sept of 2006):

Originally Posted by Coban
Here the way I see it. There are 2 situations.

1. Shackles and Hangers
Using Shackles and hangers means the the level of the axle in relation to the frame and drivetrain has changed. In this case, you need to angle the front of the differential down slightly. Since Chevy's have the leaf springs on the top, you need to install the Shim with the FAT SIDE FORWARD.

2. Shackles only
Using shackles only means that you change the level of the axle AND the Rotation of it. (Refer to Colby's diagrams on first page) The front of the differential is now pointing down, so you need to angle it back upward. You need to install the shims with the FAT SIDE BACK.

Does everyone agree with this? Of course, there are 2", 3", 4",.... drops so not everyone is gonna be the same. Some trucks dont ever need them, but its a good idea to keep in stock spec. Vibrations tell you something is f**ked up.

Let me know what ya'll think.
This explains why some say fat side forward and others say fat side back. Since I have shackles only, fat side is going back. Man, this website is awesome. Thanks, guys.
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Old Jul 25, 2011 | 01:39 AM
  #14  
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Did you get your shims installed? Did it cure your vibrations? Did you ever measure the drive line angle and figure out what degree of shims you actually needed?

2°? 4°? 6°?

Summitracing.com sells them all.

Here's the link.
http://www.summitracing.com/search/P...n-Angle-Shims/

We need a 2 1/2 inch wide shim right?
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Old Aug 8, 2011 | 09:33 AM
  #15  
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Originally Posted by iregret
Did you get your shims installed? Did it cure your vibrations? Did you ever measure the drive line angle and figure out what degree of shims you actually needed?

2°? 4°? 6°?

Summitracing.com sells them all.

Here's the link.
Pinion Angle Shims - SummitRacing.com

We need a 2 1/2 inch wide shim right?
Sorry for the slow response. I've been enormously busy at work. I still haven't gotten the shims installed--haven't had time. Oddly enough, though, the vibration has slowly gotten better. Now, it is almost unnoticeable at all. I did crawl under there and look at everything, and noticed that I do have a 2-piece driveshaft. Had a buddy check my u-joints and such, and he said everything looked fine.

Does this vibration correct itself over time? And, no, I haven't just gotten used to it...it REALLY has gone away nearly.
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