Readylift SST Trail boss questions

[Flyboygt]

I've been searching around and I can't find the answer I'm looking for. I'm looking at the Readylift SST lift for the Trail Boss and their recommendation is to Not use 4wd in auto mode, somehow it can damage the 4wd. What's the problem with using Auto mode? Why would auto be different than 4H or 4L with this lift? 

Is this a problem with the truck at 4"of lift no matter the lift manufacturer?

I use auto mode for about 2 to 3 months a year where I live vs just driving around in 4H all the time so I guess this will affect my decision making with lift kits.  

My other option is going full suspension swap from Icon. 

 

Thanks all

 

[TBaganATX]

I have it a mind used during the Texas freeze last month. No issues I know of.


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[Rukus]

The TB has the axels in the "grey area" already.  (if you look they are not level).  When you add 1.75-2" they are at the end of the "tolerance".   When in auto mode the axel is at an aggressive angle and engaged.   This heats up and causes issues.   The Boots are brittle and thin as well.   Tears have been known to happen.   The real issue.. don't level.   Either lift and drop T Case or leave it as it is.   The OEM has 2" built in for tolerance.   The TB (and AK4) are already at the 2".

[Flyboygt]

Thanks for the info.. that's what I've been looking for. 

[Supercup]

Reason for the note is the axel angels are more extreme than stock and the torque on the front diff when shifting at speed can cause damage to the front diff, as the shift on the fly of auto 4wd at speed generates a lot of torque on the diff - with the geometry being stretched beyond factory specs, you are at risk of damaging your front diff.  You likely will not get it warrantied.   When kit first came out they had customer complaints about grinding noise when using auto 4WD as it shifted in and out of 4wd and then ultimatly a few that toasted the front diff.  So they added the note - to warn the customer . 

 

You face this same issue with any level kit - so it not just a RL issue - it is for any level kit that goes beyond factory specs.  I found out after the fact from several reputable off road shop in my area that it was common knowledge that if you go over 4" in lift you need a proper lift kit with diff drop bracket (so TB is 2" and RL is 2" so on the edge).  So if you use Auto 4wd with any level kit - you run the risk of damanging your front diff - does not mean you will - but it could happen and if it does it likely will not be covered under warranty.

 

If you can get a proper lift kit from Zone or BDS or others that is more costly - you will eliminate this risk for about $650 (the difference in price of a RL SST vs a Zone 2" lift - no shocks).  I ran my 2019 AT4 with RL SST kit for 10k miles - no issues, but I never used auto 4wd - I did use 4H with no issues. 

 

Zone - https://zoneoffroad.com/products/4-in-ifs-suspension-lift-kit-2019-2020-chevy-trail-boss-gmc-at4?variant=39266940878936

 

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

 

Here are photos of my 2019 AT4 with RL SST kit - see the angle of the axels (sorry for crappy photo) - then a photo of my 2020 AT4 with proper BDS lift kit (2.5" - so 4.5" overall).  

 

2019 GMC AT4 - Stock 275/65/18 tires - axel angles are pretty extreme 

1

 

2020 GMC AT4 - stock 275/65/18 tires  - note axels are dead level - better than stock 

 

Edited March 15, 2021 by Supercup

[lapoolboy]

7 hours ago, Rukus said:

The TB has the axels in the "grey area" already.  (if you look they are not level).  When you add 1.75-2" they are at the end of the "tolerance".   When in auto mode the axel is at an aggressive angle and engaged.   This heats up and causes issues.   The Boots are brittle and thin as well.   Tears have been known to happen.   The real issue.. don't level.   Either lift and drop T Case or leave it as it is.   The OEM has 2" built in for tolerance.   The TB (and AK4) are already at the 2".

🥱

 

Edited March 16, 2021 by lapoolboy

[Flyboygt]

Thanks for the detailed write up. 

 

I'm not trying to start a holy war over a lift! I just don't want to fry my band new rig because of 4wd auto! 

I'm not trying to be a cheap ass I was honestly looking at Icon stage 2 kit when I came across the readylift and noticed all the issues with the height.

What I gather is that no matter what kit is used if you get to 4" without drop brackets you are going to kill your diff or axles. 

[dane0254]

Let us know what you get. I have a 2020 TB and love it, but sometimes going a little higher seems tempting. 

[Flyboygt]

Will do.. just looks like my research is going to get a bit deeper. I'm not a fan of the full 4"over stock (I don't want a 6"lift) I really wanted a front level and to get 35's on it, but if a level means I am strapping a grenade to the diff/axles then I guess that's out... Back to the drawing board!

Maybe I just find a smaller lift block for the rear!

[lapoolboy]

I'll just leave this right here...

 

Bilstein 6112 for TB/AT4.  Set on highest clip to bring front up 1.2" for a total of 3.2" up front....levels the truck nicely.

[Flyboygt]

No need to leave it!

 

Where did you buy it? Model number? I am more into coilover setup over lift pucks.

Edited March 16, 2021 by Flyboygt

[Rukus]

3 hours ago, lapoolboy said:

I'll just leave this right here...

 

Bilstein 6112 for TB/AT4.  Set on highest clip to bring front up 1.2" for a total of 3.2" up front....levels the truck nicely.

B ut your axel angles will still be out of wack and the upper control arm is not happy (ball joint)

[lapoolboy]

8 minutes ago, Rukus said:

B ut your axel angles will still be out of wack and the upper control arm is not happy (ball joint)

The axle and ball joint angles are no more "out of whack" than they were when stock.  The suspension can only travel through a specific range of motion bound by its physical limits; i.e. UCA droop stops and bump stops.  Most trucks won't even see these two extreme ends of the articulation angles during normal operation, everything else is within the same range of motion as the stock setup.  The axles and ball joints are engineered to function properly within these parameters and have plenty of margin built-in.  If you put the truck on a lift and take the front struts off, you can cycle the suspension from total droop to total compression with a physical "stop" at each end.  The ball joints and axles are designed to work inside this envelope (plus a little margin each way for reliability).  This doesn't change simply by adding an aftermarket lift strut.  Limits are just that.

 

[lapoolboy]

I'm fairly certain one of the biggest names in suspensions - Bilstein - knows this as well.  That's probably why they have no problem putting out a product, with warranty, that lifts the front of my truck 1.2".

[Flyboygt]

Ok gents.. here is what I've found.. Camburg took the bilstein kit to the next level with control arms. 1800 and I get what I want without a built-in grenade! 

 

 https://camburg.com/shop/suspension/performance-suspension/camburg-chevy-1500-19-bilstein-6112-performance-kit/