2018 Sierra with Zone 4.5" lift now shudders

[Knowles101]

So I just installed the Zone 4.5" lift on my 2018 Sierra 1500 with fox 2.0 shocks on the rear as well as the add a leaf and Bilsteins 5100 on the front. Took it out for a spin and when accelerating from about 20 km/h to 60 km/h I get a shudder/vibration in the drive line. This happens either when I am accelerating or braking through this speed range but is not there when I shift it in to neutral. The truck had no issues or vibrations prior to the lift kit install. Any ideas?

[1SLOW1500]

Drive shaft angles.

Sent from my SM-N960U using Tapatalk

[Snowcamo]

Was thinking rhe same or pinon angle.

[1SLOW1500]

Was thinking rhe same or pinon angle.

Or still pinion angle do to axle wrap. Also need better u bolts and torque them down once the angle is right.

Sent from my SM-N960U using Tapatalk

[Knowles101]

Damn I was afraid that might be the issue.

[FlipZ71]

2 hours ago, Knowles101 said:

So I just installed the Zone 4.5" lift on my 2018 Sierra 1500 with fox 2.0 shocks on the rear as well as the add a leaf and Bilsteins 5100 on the front. Took it out for a spin and when accelerating from about 20 km/h to 60 km/h I get a shudder/vibration in the drive line. This happens either when I am accelerating or braking through this speed range but is not there when I shift it in to neutral. The truck had no issues or vibrations prior to the lift kit install. Any ideas?

Knowles , 

 On my 2015 I had started with the same set up .  I had the same vibration but only when I put it in 4 wheel drive.  

 The issue turned out to be the drive shaft was not marked before removing.  So when they reinstalled it , was not clocked correctly.  The lift instructions for zone 4.5 state this step clearly.  The install shop never read it. 

 Anyway after I flipped it issue was gone. 

   This may not be your issue but it's a start. Read through the instructions and question everything you'll find it. 

 Oh... and I also had the additional leaf but used a smaller block....   rear pinion angle is good. 

[Knowles101]

So if they didn't mark it then how do I know at what point to re-install it at? Do I just turn the drive shaft 90 degrees and bolt it back together?

[FlipZ71]

9 hours ago, Knowles101 said:

So if they didn't mark it then how do I know at what point to re-install it at? Do I just turn the drive shaft 90 degrees and bolt it back together?

Let me clarify...   mine vibration was only in 4 wheel drive. The front drive shaft is what had to be clocked correctly. 

 Shouldnt be any reason to remove the rear. 

  But yes all I did was unbolt the drift shaft on pinion end , rotated the yoke , bolted it back up , problem gone