Added Blocks in Rear...Grinding Noise in Rear

My brother has an 06 with spindles and coilovers up front for about 6.5 inches of lift. In the rear he has a Deaver 12 Pack but it has since settled so today he added 1.5'' blocks. It sits nice and level and it's only going to see the pavement so he didn't mind adding the blocks.

The problem though is after installing them whenever he brakes somewhat hard there is a grinding sound. It's not the brakes since those have recently been replaced. However you know that sound when you are wearing into your rotors, well it sounds like that almost, more so from the center of the truck. Could it have to do with the driveshaft? There aren't any wobbles though.

Any ideas?

 

Is it in the towards the front or back? Is it like a high screeching noise?

 

It's like right under the cab where the truck bed begins and its like a low grinding that last for about 2 secs as you brake hard.

 

That was gonna be my guess. I never had that though when I had that much lift in front, but then again my rear was stock hah.

 

i have a buddy of mine who owns his own shop and he owns a tacoma and he said whenever your lifting the rear over 2.5'' angles on the drive shaft can alot of wear and tear and make weird noises i would look into somehow straightening that angle out a little more now that its lifted alot higher

 

Ya I was thinking it was from the angle of the drive shaft as well.

Update: He drove it around a couple miles today and there is a noticeable vibe.

I think he might just take the blocks off and lower the front a little bit if he can't figure out how to fix this.

 

Blocks removed grind & vibe gone as well

 

buy tapered rear blocks for a better driveline angle. common problem on jeeps