2021 Sierra At4 level kit installed now I need a differential drop kit anyone run into this problem.

[Tyee]

Can’t find a fix for the level kit installed on my at4, now I’m being told don’t run 4 auto or possible cv damage?!?   Nobody sells a current diff drop spacers kit.  I’m ordering the supreme suspension # a4302 kit for years 01-08 Silverado/Sierra.  Anyone got any fixes other than buying a entire new suspension.  Still on my stocks 18” factory wheels. After the diff drop I’ll add 22” 12.5x10-18 with 33” tires. Thanks guys

[clowe1243]

Do all AT4s have Adaptive ride?  I know alot of kits used to say they would fit the same as the Silverados, but the angles were off a bit.  I think BDS made the kit for Sierras and proved they weren't the same.

[todd308]

I don't believe any AT4's have adaptive ride, that's only in the Denali package. 

 

The only way I know to get a diff drop for them is in the real lift kits, I haven't seen anyone selling them separately.   The only good way to lift/level these trucks is to either remove the spacer out of the rear to drop it closer to the front, or pay for a real 2.5-4" etc. lift that includes a diff drop.   

 

The problem is GM went the cheapest possible route with the AT4 and they didn't correct the angles with their "2 inch lift" which up front is really more like 3/4" and 2.5" in the back (which is why the AT4's look so much worse as far as the back end being higher than the front that the non-lifted Sierras).  I park next to another non-AT4 at work and my front end is only 3/4" higher than his, but my back end is almost 2.5" higher and mine looks much more "un-level".  So because the angles are already not great on the AT4 factory, adding any more up front causes problems.   One of the reasons some of the level kits say not to use 4-auto is when it kicks in it's a lot more stress than just using 4 high, and since the angles are at their limit (or really past what the limit should be) 4-auto is more likely to cause a failure.  

 

We see plenty of pics on the facebook groups of guys putting on a level without replacing the UCA's and later having the UCA fail and a wheel separate because the factory UCA/ball joint angle is pretty bad on the AT4 even stock, add a level to it and it's really ugly.   Even if you do fix the UCA issue, the CV angle is still a problem unless you drop the diff. 

[Freeagnt54]

Watching. I’m hesitant to lift the front more than an inch with out some kind of diff drop.

 

[Dunn]

On 9/3/2021 at 9:15 AM, todd308 said:

I don't believe any AT4's have adaptive ride, that's only in the Denali package. 

 

The only way I know to get a diff drop for them is in the real lift kits, I haven't seen anyone selling them separately.   The only good way to lift/level these trucks is to either remove the spacer out of the rear to drop it closer to the front, or pay for a real 2.5-4" etc. lift that includes a diff drop.   

 

The problem is GM went the cheapest possible route with the AT4 and they didn't correct the angles with their "2 inch lift" which up front is really more like 3/4" and 2.5" in the back (which is why the AT4's look so much worse as far as the back end being higher than the front that the non-lifted Sierras).  I park next to another non-AT4 at work and my front end is only 3/4" higher than his, but my back end is almost 2.5" higher and mine looks much more "un-level".  So because the angles are already not great on the AT4 factory, adding any more up front causes problems.   One of the reasons some of the level kits say not to use 4-auto is when it kicks in it's a lot more stress than just using 4 high, and since the angles are at their limit (or really past what the limit should be) 4-auto is more likely to cause a failure.  

 

We see plenty of pics on the facebook groups of guys putting on a level without replacing the UCA's and later having the UCA fail and a wheel separate because the factory UCA/ball joint angle is pretty bad on the AT4 even stock, add a level to it and it's really ugly.   Even if you do fix the UCA issue, the CV angle is still a problem unless you drop the diff. 

exactly......i have a AT4 kit on elevation and currently @ 3in front.....i wont go higher or use 4WD until i have drop kit....thankfully i dont need it........running stock tires but it wouldnt matter, tires dont alter angles like lifts do......i do have a UCA and did buy a diff drop but it isnt for T1 trucks, says it will fit but its puck spacers like older gen and new trucks are different

Edited September 10, 2021 by Dunn

[Unwrntd]

My BDS 4" lift came with a differential drop.