2011 gmc front suspension issue

[Racerrick]

Hey guys. Iv got a 2011 gmc seirra 2500HD. regular cab long box 6.0L automatic. We been having a issue where when pulling our dump trailer loaded with material driving down the road and when stopping the steering shakes violently. We checked the complete front suspension ball joints were all good we replaced the idler, pitman arm, center link, steering column to gear box shaft plus added a steering stabilizer as well. tires are all wearing nice and straight to. We also done brake pads and rotors. This truck has been pulling trailers most of its life. Any help would be greatly appreciated. I have done everything I can think would be the issue. thank you in advance

Edited April 20, 2021 by Racerrick

[C/K Man]

Do you experience the problem only when braking?  This may be an antilock brake system issue.

[Racerrick]

yes it appears only when braking. I have heard that it can possibly be a antilock issue but I don't have a antilock light on or any antilock codes either. So I'm not exactly sure where in the system it would be the issue.

[C/K Man]

And I take it the Stabilitrack light does not come on when this is happening, right?  Only other thing I can think of is the weight of the trailer pushing on the truck while braking is causing the suspension to move to a toe out position.  Alignment is good?

[Racerrick]

No the stabilitrack light does not come on either. That's what iv been leaning toward is the toe out when breaking. Or myself and my son were wondering if the rear spring could be warn out so its in a sense causing the toe out as well. Alignment has not been checked. iv run that past my boss and got out voted on taking in to have that checked. The only front parts its needed thus far is the idler and pitman arm. 

[It's Tim]

ABS wheel sensor issue.

[Racerrick]

We did replace both front hub assemblies in late 2019. We do not have a antilock light on either though. that is what is making all this the most confusing.