Is there a level for the AT4 that keeps auto 4wd?

[NonTypicalCPA]

I love auto 4wd during our Michigan winters. I’d rather have it over a level. But if there is a level that works with the auto 4wd I’d like to know. 

[Tjeli]

50 minutes ago, NonTypicalCPA said:

I love auto 4wd during our Michigan winters. I’d rather have it over a level. But if there is a level that works with the auto 4wd I’d like to know. 

Do you ever haul or tow anything with your truck?  I personally don't think the AT4s look that "unlevel" in stock form and the leveled ones look dorky with a case of beer in the back.  That combined with guys breaking ball joints by leveling the pre lifted trucks makes me want to keep it stock.

 

-Eli

[newdude]

What do you mean by "keeps Auto 4wd"?

 

AT4 comes standard with auto 4wd.  

[NonTypicalCPA]

Most levels say you should not run in auto 4wd after install. 

[Tjeli]

38 minutes ago, NonTypicalCPA said:

Most levels say you should not run in auto 4wd after install. 

Which is a huge red flag in my mind for CV angles.  Even though they look fine.

[amxguy1970]

^ This. Stacking leveling kits and having to be cautious about what to run would have me second guessing my choices. Sprinkle in the fact that a level truck looks nose high due to the body and any kind of weight in the back for the occasional haul would look like it's over loaded due to sag.

 

Tyler

[Snakes709]

I have zero intentions of levelling my truck but this is news to me and got me curious If some kits recommend not using auto 4wd, what about 4hi or 4lo? What does the auto have to do with anything? If you cant use any of the 4wd’s then why the **** would anyone get a 4wd truck?

[Ryguy]

Any 4x4 truck without a straight axle in the front is going to run the risk of damaging and even snapping the cv’s. The more you weight you run (Bigger tires/wheels), and the higher the truck is lifted means you’re putting extra strain on components that weren’t designed for that by GM engineers. So yes it’s a risk, however most people who are leveling their trucks aren’t looking to do any serious off roads. These trucks are not built to go to Moab, we don’t even have a selectable locker, so I would assume 90% of guys buying 4 wheel drive trucks almost never use it. Lifting a truck is mostly for looks so cruising around on the highway and the occasional 4auto in wet or gravel roads shouldn’t be a problem. I would not recommend dropping to 4lo and trying to crawl over the rubicon...even with a stock truck.   

[davidlewis1010]

ReadyLIFT has a leveling kit specifically designed for the AT4/Trail Boss that comes with new upper control arms to allow for proper ball joint and C/V axle angle.  There is no note about not using Auto mode.  I have this kit, and have had no issues with it.  I do see the note about not using the auto mode in the ReadyLIFT 2.0” lift kit for the AT4/TrailBoss that uses the same front end components as the level kit.  It’s also in every other lift kit made by them.  I am curious if the reason has something to do with the raised center of gravity on the truck, and this is a way for them to cover themselves in the event of an accident.  

https://www.readylift.com/2-25-front-leveling-kit-w-control-arms-at4-trail-bossgm-1500-truck.html

[Supercup]

3 hours ago, davidlewis1010 said:

ReadyLIFT has a leveling kit specifically designed for the AT4/Trail Boss that comes with new upper control arms to allow for proper ball joint and C/V axle angle.  There is no note about not using Auto mode.  I have this kit, and have had no issues with it.  I do see the note about not using the auto mode in the ReadyLIFT 2.0” lift kit for the AT4/TrailBoss that uses the same front end components as the level kit.  It’s also in every other lift kit made by them.  I am curious if the reason has something to do with the raised center of gravity on the truck, and this is a way for them to cover themselves in the event of an accident.  

https://www.readylift.com/2-25-front-leveling-kit-w-control-arms-at4-trail-bossgm-1500-truck.html

 

The short answer to the OP's question is that any "level" kit for AT4/Trail boss may impact use of auto 4WD.  CV angles with level are to extreme in the front, no matter the level kit mfg.  the issue is when the truck moves into 4wd under some conditions the front diff suffers extreme torque and it can be severely damaged.  RL added a note to the SST kit after a few months, due to customer complaints of loud noises and a few customers who complained they lost their front diff's when using 4WD auto.  When you speak with knowlegable shops they all seem to agree that 4" of lift is the point of no return - so 2" added to AT4 + 2" more. 

 

Unfortunately the RL level kit, noted above has no mention of the "auto 4WD" function impact, but their SST kit they have the following note  "NOTE:  Use of Auto 4 HI feature not recommended",  the only difference is the rear block.  It is 1.75" level - so 3.75" overall, where SST states it is a 2" level (so 4" overall).  The upper control arms correct the angles for the upper ball joints, but do nothing for the CV axel angles. 

 

I had a 2019 AT4 Carbon Pro - I installed the RL SST kit - CV angles were not good - no auto 4WD.  I traded in for a 2020 AT4 Carbon Pro with trailer tow mirros, as I tow a lot and I did not want any issues up front.   Pictures below. 

 

For the 2020 I went with BDS 2.5" lift - which provides proper CV angles (better than AT4 from Factory).  I have the full program with Fox 2.5 DSC coilover shocks - so a $4,700 deal installed.   I love it, but it is a lot of money if you don't go offroad much and just want a level.  

 

If you want to use Auto 4WD, you will need a lift kit that lowers your front diff, to keep CV angles within OEM spec.  You can buy BDS or Zone 4" lift kit without the Fox shocks and save some $ - but you are still looking at $2,086 for BDS and $1,300 for zone (which is made by BDS).   But that is 6" over stock -so 4" over your AT4 OEM ride height - currently they do not offer the 2.5" lift kit without the fox coliovers (which is 4.5" vs stock 4" for AT4).  There are other mfg. of proper lift kits as well that can get you same outcome, as long as they have a diff lowering brackets in their lift kit.  Zone is the best overall value, for just the lift. 

 

RL SST: https://www.readylift.com/at4-trail-boss-plus-2-0-sst-lift-kit-gm-1500-at4-trail-boss-4wd-2019.html

BDS:  https://bds-suspension.com/product?kid=749H

Zone:  https://zoneoffroad.com/products/4-in-ifs-suspension-lift-kit-2019-2020-chevy-trail-boss-gmc-at4?variant=33403092729944

Below are photos of my 2019 with RL SST kit and my 2020 with BDS 2.5" kit - you will note the CV angles are level on the BDS and are quite extreme on the RL (note boots).

 

There are no short cuts for AT4/Trailboss to do a proper level or lift.  Only other options other have tried is a shorter block in the rear for the level.  That is the cheapest option, but may not work the best. 

 

2019 AT4 - Ready Lift SST Kit - CV Angels - level ground 

 

2020 AT4 BDS 2.5" Lift Kit CV angles - level ground 

 

2019 AT4 Stock 

 

2019 SST RL Level - dead level 

 

2020 AT4 BDS 2.5" Lift - Fox shocks - a little rake 

Edited October 25, 2020 by Supercup

[davidlewis1010]

7 hours ago, Supercup said:

 

The short answer to the OP's question is that any "level" kit for AT4/Trail boss may impact use of auto 4WD.  CV angles with level are to extreme in the front, no matter the level kit mfg.  the issue is when the truck moves into 4wd under some conditions the front diff suffers extreme torque and it can be severely damaged.  RL added a note to the SST kit after a few months, due to customer complaints of loud noises and a few customers who complained they lost their front diff's when using 4WD auto.  When you speak with knowlegable shops they all seem to agree that 4" of lift is the point of no return - so 2" added to AT4 + 2" more. 

 

Unfortunately the RL level kit, noted above has no mention of the "auto 4WD" function impact, but their SST kit they have the following note  "NOTE:  Use of Auto 4 HI feature not recommended",  the only difference is the rear block.  It is 1.75" level - so 3.75" overall, where SST states it is a 2" level (so 4" overall).  The upper control arms correct the angles for the upper ball joints, but do nothing for the CV axel angles. 

 

I had a 2019 AT4 Carbon Pro - I installed the RL SST kit - CV angles were not good - no auto 4WD.  I traded in for a 2020 AT4 Carbon Pro with trailer tow mirros, as I tow a lot and I did not want any issues up front.   Pictures below. 

 

For the 2020 I went with BDS 2.5" lift - which provides proper CV angles (better than AT4 from Factory).  I have the full program with Fox 2.5 DSC coilover shocks - so a $4,700 deal installed.   I love it, but it is a lot of money if you don't go offroad much and just want a level.  

 

If you want to use Auto 4WD, you will need a lift kit that lowers your front diff, to keep CV angles within OEM spec.  You can buy BDS or Zone 4" lift kit without the Fox shocks and save some $ - but you are still looking at $2,086 for BDS and $1,300 for zone (which is made by BDS).   But that is 6" over stock -so 4" over your AT4 OEM ride height - currently they do not offer the 2.5" lift kit without the fox coliovers (which is 4.5" vs stock 4" for AT4).  There are other mfg. of proper lift kits as well that can get you same outcome, as long as they have a diff lowering brackets in their lift kit.  Zone is the best overall value, for just the lift. 

 

RL SST: https://www.readylift.com/at4-trail-boss-plus-2-0-sst-lift-kit-gm-1500-at4-trail-boss-4wd-2019.html

BDS:  https://bds-suspension.com/product?kid=749H

Zone:  https://zoneoffroad.com/products/4-in-ifs-suspension-lift-kit-2019-2020-chevy-trail-boss-gmc-at4?variant=33403092729944

Below are photos of my 2019 with RL SST kit and my 2020 with BDS 2.5" kit - you will note the CV angles are level on the BDS and are quite extreme on the RL (note boots).

 

There are no short cuts for AT4/Trailboss to do a proper level or lift.  Only other options other have tried is a shorter block in the rear for the level.  That is the cheapest option, but may not work the best. 

 

2019 AT4 - Ready Lift SST Kit - CV Angels - level ground 

 

2020 AT4 BDS 2.5" Lift Kit CV angles - level ground 

 

2019 AT4 Stock 

 

2019 SST RL Level - dead level 

 

2020 AT4 BDS 2.5" Lift - Fox shocks - a little rake 

Did your 2019 use the stock upper control arms?  That angle doesn’t look good.  Your 2020 kit looks ideal, but it should for the cost. Here is a pic of my 2020 with the RL level kit with new upper control arms.  The CV angle is not severe like your 2019 was.  This kit didn’t come out until 2020, so I am curious if maybe you used something different.  This kit splits the spacers between the top and bottom of the coil over.  Putting a spacer on the bottom of the coil over moves the control arm further away while leaving the ball joint and cv angle somewhat unchanged.  I agree that lowering the front diff is the correct way to go to correct the cv angles.  I must disagree with your comment that the upper control arm does not impact CV angles.  The longer arms push the top of the spindle outward to help center the lower ball joint.  This also changes the angle on the cv axle.  

[Justin Vaughn]

2 hours ago, davidlewis1010 said:

ReadyLIFT has a leveling kit specifically designed for the AT4/Trail Boss that comes with new upper control arms to allow for proper ball joint and C/V axle angle.  There is no note about not using Auto mode.  I have this kit, and have had no issues with it.  I do see the note about not using the auto mode in the ReadyLIFT 2.0” lift kit for the AT4/TrailBoss that uses the same front end components as the level kit.  It’s also in every other lift kit made by them.  I am curious if the reason has something to do with the raised center of gravity on the truck, and this is a way for them to cover themselves in the event of an accident.   

https://www.readylift.com/2-25-front-leveling-kit-w-control-arms-at4-trail-bossgm-1500-truck.html

More info here about the RL advisory to not use it..

 

[Supercup]

On 10/25/2020 at 7:30 PM, davidlewis1010 said:

Did your 2019 use the stock upper control arms?  That angle doesn’t look good.  Your 2020 kit looks ideal, but it should for the cost. Here is a pic of my 2020 with the RL level kit with new upper control arms.  The CV angle is not severe like your 2019 was.  This kit didn’t come out until 2020, so I am curious if maybe you used something different.  This kit splits the spacers between the top and bottom of the coil over.  Putting a spacer on the bottom of the coil over moves the control arm further away while leaving the ball joint and cv angle somewhat unchanged.  I agree that lowering the front diff is the correct way to go to correct the cv angles.  I must disagree with your comment that the upper control arm does not impact CV angles.  The longer arms push the top of the spindle outward to help center the lower ball joint.  This also changes the angle on the cv axle.  

 

2019 did have Ready Lift Upper control arms - however they are not "longer" per say - they just change the angles, to correct the geometry of the upper ball joint, to reduce the wear.  

 

Below is video from Ready lift that walks through their AT4/Trail Boss level kit and SST kit.    See minute 1:37 - 2:04, 3:55 - 4:20 and 5:20 - 5:40 to hear about control arms.  If you stop video at 4:22 you can see the control arms (stock and Ready lift) - if you measure from the bolt hole to the tip and see they are basically the same length.

 

I do agree  there are many after market control arms that are longer, but it does not appear to be the case here.   Also note the "thicker" end of the RL UCA, reduces tire clearance on the inside versus the stock UCA's - see photo below of clearance with stock 27/65/18's on a 18mm offset Method NV 18"x9" wheel.  That photo is my 2019 with RL SST kit installed.  With stock wheels, which are 26 mm offset, I could not get my finger in there - too close.   That is about 5/16's of an inch of clearance. 

 

  

 

LINK: 

 

Edited October 29, 2020 by Supercup

[Mark Scannura]

On 10/25/2020 at 11:34 AM, davidlewis1010 said:

ReadyLIFT has a leveling kit specifically designed for the AT4/Trail Boss that comes with new upper control arms to allow for proper ball joint and C/V axle angle.  There is no note about not using Auto mode.  I have this kit, and have had no issues with it.  I do see the note about not using the auto mode in the ReadyLIFT 2.0” lift kit for the AT4/TrailBoss that uses the same front end components as the level kit.  It’s also in every other lift kit made by them.  I am curious if the reason has something to do with the raised center of gravity on the truck, and this is a way for them to cover themselves in the event of an accident.  

https://www.readylift.com/2-25-front-leveling-kit-w-control-arms-at4-trail-bossgm-1500-truck.html

Quote from ReadyLift in writing: "We don't suggest 4wd auto to be used " This was in reference to a list of questions I wrote them on the 1.75 AT4/Trail Boss level kit. That kit includes new UCAs. Congnito and BDS both told me same about their level kits. 

Edited August 15, 2023 by Mark Scannura

[Andymarco]

Is the 4wd auto problem only in the at4? Or does it happen with a lower trim level like the elevation?