My friend has a 94 C1500 RCSB, I think the drop is a 4-6...
Anyway, to make a long story short, He needed new U-joints so he took it to have them replaced. After the change it kept throwing them out so the shop checked the angle on the rearend and told my friend it was at a 10* angle...

So, I was thinking he would need, maybe a 6* Shim/Wedge but I called Mcgaughys and they told me a 2* would fix the issue???

Why would I use a 2* when its at a 10* now? In theory, wouldn't that only bring it to 8* correct?

 

Really? Nobody has any input?

 

If I'm thinking correctly, a 2* shim will take 4* out total. 2* on both ends.

 

Is the trans output shaft raised up? I have a 4 inch drop in the rear and in order to get my driveline angles correct I needed to raise my output shaft an inch and then shim the rear end. I have a thread called "4l80e output shaft loose, am I screwed?" If you find it it goes through my driveline solution. To answer your question, if you want to adjust 6 degrees you will need a 6 degree shim. You need to know the angle at the front and rear u joint first. If the front joint is at 8 degrees and you adjust the rear to 4 degrees it's going to have a bad vibration.