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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: SUX2BU99 on August 14, 2009, 10:19:27 am

Title: Axle shims for pinion angle
Post by: SUX2BU99 on August 14, 2009, 10:19:27 am
I was reading some interesting info on driveline vibrations and one described a cyclic driveline vibration that can be caused by pinion angle being out of alignment. Usually an issue with either lowered or lifted trucks. I found this great article about a kit DJM makes to try and correct this:
http://www.stylintrucks.com/Articles/suspension-djm-pinionshims/article.aspx

I lowered a previous truck of mine and the blocks I used had angle correction built into them and I had no problems with vibrations. I think I might try this kit if my axles and driveshaft prove to be straight and my tires balanced. I'm going to crawl under there too though and see if I can measure the angle of the pinion versus the driveshaft.  Anybody do these shims before?
Title: Re: Axle shims for pinion angle
Post by: Captkaos on August 14, 2009, 04:22:39 pm
Of all the trucks I have ever lowered in the 73-87 variety, only the longbeds required shims.
Title: Re: Axle shims for pinion angle
Post by: SUX2BU99 on August 16, 2009, 09:27:40 pm
I drove my truck today, wonky rear gears and all, and oddly I wasn't feeling it or felt it very little.

Here is my axle and driveshaft. There is a visible difference in the pinion angle vs driveshaft angle. Nothing to worry about?

Title: Re: Axle shims for pinion angle
Post by: Captkaos on August 17, 2009, 07:57:25 pm
That is normal.  If you are concerned, get an angle finder and put it on the cap on the yoke and then do the same on the output yoke, they should be within 2 degrees of each other.

Keep in mind if you werent lowered, that angle would be larger.
Title: Re: Axle shims for pinion angle
Post by: SUX2BU99 on August 18, 2009, 10:08:42 am
Okay, well that's good to know. Thanks for the input.