Grinding noise after 6 inch zone lift install.

[Trucker1]

Installed a 6 inch zone lift on my 98 2 door tahoe with autotrac and I am getting a grinding noise when I am decelerating. Almost sounds like a worn pinion bearing but have checked and replaced bearings in rear axle with no change in the noise. Did not have this noise until I installed the lift.

 

[618 Syndicate]

Did you shim the diffs?

 

[Trucker1]

Yes lift blocks are tapered towards the front. Thinner side of block towards the front.

 

[smdk2500]

Yes lift blocks are tapered towards the front. Thinner side of block towards the front.

Wouldn't having the thin part pointing towards the front angle the pinion down not up? Or is my brain not working quite right this morning.
*Edit*
My brain is not working. Please disregard my comment.

 

[618 Syndicate]

Can you figure out exactly where the noise is coming from?

 

[Hipster]

Sure the noise is coming from the back? I know other lifts call for a different drive shaft with autotrack equipped trucks but I believe it's the front driveshaft needing a cv style joint.

 

[Trucker1]

Having a new driveshaft made now, so no drive shaft going to front axle. I am thinking I might be a bearing going down in transfer case.

 

[TylerZ281500]

could be a few things, i dont do tapered blocks. they give them to you to take up the angular difference of the new height between output of case and axle pinion so you dont have to lengthen a driveshaft, however.......typically its still not 100% bottom the slip yoke into the case and you should have 1.5" sticking out is proper engagement, if thats not engaging that way it could be the output bearing taking up that excessive load, or it could be the pinion working the u joint at a different angle now.

 

[Trucker1]

What could I use besides tapered blocks? I did have my rear drive made to proper lift length but still have noise.

 

[b454rat]

Blocks are cheaper than new lifted springs. Can get lift springs are a shackle flip. Nothing wrong with using blocks. GM used them in their early 4wd’s, Ford n Dodge used em up to the 90s, maybe later haven’t paid much attention. There tapered to get the driveline close to stock, has nothing to do with not lengthening the driveshaft. I put a 9” lift on a square n didn’t lengthen the driveshaft. To me sounds like a pinion bearing. Coasting it’s there but on the gas it goes away?