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19 denali 3" fabtech lift and vibration issues in AWD

1qwktrk
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1qwktrk New Member

1qwktrk

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The other day I installed a 3" Fabtech lift on my dads 19 denali 6.2 with ARC. lift install went smoothly for the most part, one bad piece of hardware and poor instructions for a few things. interestingly enough the ones on the website differed from the printed ones in the kit.

 

Anyway my issue is now it has a vibration when over 55 mph while in Auto 4WD/AWD setting. soon as you hit the button for 2wd only it goes away.

Im hoping this just isnt an issue from the increased ride height and he can no longer run awd at speed. actually hoping i possibly did something wrong that caused the issue. but front halfshafts look good and not really at any extreme angle, there are no odd noises or clunking.

lift just consisted of 2.5" strut spacer and .5" spring preload spacer with new upper A arms. alignment came out pretty good no issues there. Tires are balanced correctly.

90+ in 2wd and not the slightest shake, but in auto it starts just about 55 and gets worse the faster you go.

any insight? diff drop kit to fix angles required? Something I may have blown it on with half shafts on install? (they didnt even come out just removed the hub nut to let them slide out of the hub a little to pull the knuckle out of the way.

 

Any one else have same lift on the same truck?

 

PXL_20201030_165421931.jpg

PXL_20201031_165821324.jpg

Jav_eee Enthusiast

Jav_eee

Posted
Posted

You shouldn’t really be driving around in auto on dry pavement but because the issue is present while engaged my first guess would be the angle of the front driveshaft.


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WACKEM_G Enthusiast

WACKEM_G

Posted
Posted
You shouldn’t really be driving around in auto on dry pavement but because the issue is present while engaged my first guess would be the angle of the front driveshaft.


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I have read people tearing up there trucks because of these lift/level kits while using the awd, some kits actually warn of this in the fine print. Angles for ur driveshaft are not rite! A lift kit from bds or other decent kit will correct this with relocation brackets.


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1qwktrk New Member

1qwktrk

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21 hours ago, Jav_eee said:

You shouldn’t really be driving around in auto on dry pavement but because the issue is present while engaged my first guess would be the angle of the front driveshaft.


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auto/AWD was designed to be run full time if wanted, but I am thinking front half shafts arent at a happy angle

9 hours ago, WACKEM_G said:


I have read people tearing up there trucks because of these lift/level kits while using the awd, some kits actually warn of this in the fine print. Angles for ur driveshaft are not rite! A lift kit from bds or other decent kit will correct this with relocation brackets.


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bds only sold a 6" kit and thats too much. 

3 hours ago, redwngr said:

Does that lift include parts to lower the front differential?

 

 

It does not, only 2.5" leveling spacer over the strut and a .5" spring preload spacer. does someone make a 1-2" diff drop kit?

WACKEM_G Enthusiast

WACKEM_G

Posted
Posted
It does not, only 2.5" leveling spacer over the strut and a .5" spring preload spacer. does someone make a 1-2" diff drop kit?

They make 1.5,2.5, 4,6in kits


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1qwktrk New Member

1qwktrk

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Posted
6 minutes ago, WACKEM_G said:


They make 1.5,2.5, 4,6in kits


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they only make 4' and 6" for denali with ARC

WACKEM_G Enthusiast

WACKEM_G

Posted
Posted
they only make 4' and 6" for denali with ARC

Aghh ok looking at my truck! 48b2e27f81ff1f74e4d13972f621651a.jpg


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Grey3liter4x4 Enthusiast

Grey3liter4x4

Posted
Posted
On 11/7/2020 at 6:58 PM, 1qwktrk said:

The other day I installed a 3" Fabtech lift on my dads 19 denali 6.2 with ARC. lift install went smoothly for the most part, one bad piece of hardware and poor instructions for a few things. interestingly enough the ones on the website differed from the printed ones in the kit.

 

Anyway my issue is now it has a vibration when over 55 mph while in Auto 4WD/AWD setting. soon as you hit the button for 2wd only it goes away.

Im hoping this just isnt an issue from the increased ride height and he can no longer run awd at speed. actually hoping i possibly did something wrong that caused the issue. but front halfshafts look good and not really at any extreme angle, there are no odd noises or clunking.

lift just consisted of 2.5" strut spacer and .5" spring preload spacer with new upper A arms. alignment came out pretty good no issues there. Tires are balanced correctly.

90+ in 2wd and not the slightest shake, but in auto it starts just about 55 and gets worse the faster you go.

any insight? diff drop kit to fix angles required? Something I may have blown it on with half shafts on install? (they didnt even come out just removed the hub nut to let them slide out of the hub a little to pull the knuckle out of the way.

 

Any one else have same lift on the same truck?

 

PXL_20201030_165421931.jpg

PXL_20201031_165821324.jpg

I have the Fabtech 3" with the loaded coils and shock combo.  I'm also getting a very slight vibration in AWD around 55-60.  Figured it was the 34" tires.  Also nothing in 2WD at any speed.  It just started snowing and the roads are getting icy/snowy.  Will post back once I get my truck back from the dealer for the window leak.  Not sure if it does the same thing in 4 high at those speeds in the snow yet but I'll let you know.  And yes I don't like to drive at those speeds in 4 high in the snow but straight downhill sections of road its hard to avoid it.

 

Wonder if the longer GM front axles on the factory 2" lift would fix the problem?

SilveradoRST Enthusiast

SilveradoRST

Posted
Posted (edited)

I wonder if this is a known issue that you get vibration in Auto for all the 3.5"-4" lifts out there or if this is a one off.  

Edited by SilveradoRST
Jav_eee Enthusiast

Jav_eee

Posted
Posted

 
Wonder if the longer GM front axles on the factory 2" lift would fix the problem?


They’re spinning whether in 2 or 4 wheel drive so.... probably not?



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Grey3liter4x4 Enthusiast

Grey3liter4x4

Posted
Posted
On 11/8/2020 at 9:12 PM, Grey3liter4x4 said:

I have the Fabtech 3" with the loaded coils and shock combo.  I'm also getting a very slight vibration in AWD around 55-60.  Figured it was the 34" tires.  Also nothing in 2WD at any speed.  It just started snowing and the roads are getting icy/snowy.  Will post back once I get my truck back from the dealer for the window leak.  Not sure if it does the same thing in 4 high at those speeds in the snow yet but I'll let you know.  And yes I don't like to drive at those speeds in 4 high in the snow but straight downhill sections of road its hard to avoid it.

 

Wonder if the longer GM front axles on the factory 2" lift would fix the problem?

Just got home from a day in the snow in the mountains.  In AWD there is a very slight vibration at 55 that didn't seem to get worse at higher speeds.  In 4 hi though nothing, smooth and easy.  Not sure why that is but it is.  Would still like to drop the diff to improve the axle angle.  

 

Was thinking of the longer GM front axles in the factory TB lift but unless they're designed for greater angles it doesn't address the original problem.  Still haven't found an actual diff drop kit for the 2019/2020 trucks other than Ebay.

Grey3liter4x4 Enthusiast

Grey3liter4x4

Posted
Posted
On 11/10/2020 at 2:54 PM, Grey3liter4x4 said:

Just got home from a day in the snow in the mountains.  In AWD there is a very slight vibration at 55 that didn't seem to get worse at higher speeds.  In 4 hi though nothing, smooth and easy.  Not sure why that is but it is.  Would still like to drop the diff to improve the axle angle.  

 

Was thinking of the longer GM front axles in the factory TB lift but unless they're designed for greater angles it doesn't address the original problem.  Still haven't found an actual diff drop kit for the 2019/2020 trucks other than Ebay.

Discovered why there are no diff drop kits for a 2020.  Took the time to crawl under the truck and there is no way 4 small pucks of any design are going to lower the front diff.  The front differential is bolted into several frame pieces vertically and horizontally.  There is no way that I can see you'd be able to drop the front diff without some sort of subframe or without heavy modification.  Beware of any Ebay kit that says it fits with pucks/spacers and longer bolts.  

  • 3 months later...
Fast325it Enthusiast

Fast325it

Posted
Posted

Has anyone found a fix for the new AWD/4wd vibration after installing front end lift or level?

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