After reading a lot of threads and searching the web, and finding many conflicting answer, I figured I would ask here. My truck is a 2006 single cab 4x4. Pulled the factory lift blocks and also did a 4l80e swap. After the swap I noticed the vibration around 65-70. I measured the angles today (not even positive I measured them correctly) and found t case is at -5.5°, driveshaft at -5.5°, and rear diff is pointing upward toward front of the truck at 5°. I am also getting a bad vibration on launch. Should I shim at the trans mount up? If so what is recommended, and what should my rear be set at? Thanks for any help.

 

First pic is rear diff, second is the driveshaft and last pic is at the transfer case.

 

I really always recommend measuring angles before doing any driveline modification to serve as a baseline for what is vibration free.

That being said, your angles seem good with the exception of the front u joint. There's no working angle which will eventually cause the u joint to fail.

Was the driveshaft redone for the swap? Is the yoke engagement in the trans good?

 

Yeah I'm really kicking myself for not taking measurements before I modified anything.

I did have the driveshaft shortened 1 11/16" and new u joints from fort worth gear and axle. Slip yoke does have good engagement.

 

use some 2 degree axle shims to point the pinion two more degrees down, that should be all it takes since your driveline is pretty much in a straight line right now.

 

^^^^^


You dont have proper operating angle on the Front shaft. Personally I would get the trans to go to 4.5", then match the rear end to 4.5. At that point the Driveshaft(front u joint) should have 1-1.5 degree operating angle, and the trans and rear will be bang on.

Only other thing is that drive shaft may be out of balance, but generally that wont give a shake on immediate take off.

 

Alright cool. What do you guys use to shim the transfer case up? Also, do you shim between the trans and mount, or the mount and cross member?

 

Was removing the rear blocks the only suspension mod the you did?

 

Since your truck is a 4x4 what are your front shaft angles?

 

Yeah that's it so far. I have a flip kit and parts to remove the t bars and lower the front with coilovers, but I've been waiting to install all of that until after I had the 4l80e swap stuff completely squared away. That all will hopefully be done by next week, then I'll be doing about 4/5 drop shortly after.

I didn't measure the front shaft yet.