handling problem.

fornt shocks? check air valves? leaking air bags,lines?

 

I don't think it's the steering box.How are your Tires steers and drives?This sometimes happens when you put brand new drive tires.Have you checked your alingnement lately?Some folks say it's a waste of money to do it on a semi truck but not in my experience.How old are your front spring leafes?They are getting softer with time on those trucks with front air ride and changing them might help but it's not cheap.If the bushings are worn that could be the reason to.I had the same issue on my previous truck 07 780 and changing some things helped a little but not to much.It's a heavy sleeper on air ride and it feels like the front is bouncing like a ball and the steering goes left and right and you have a hard time keeping it in a straight line like you are in a truck for a first time.Especialy if the road is bad or it's windy out.They have changed the design a little bit on the new trucks but the ride is not much different.You might also want to try factory shocks next time that might help a little too.Check the sleeper shocks and air bags the problem could be there

 

No need to change the air bags.Only when they blow.Unfortunately you have done everything and not much else you can do.Its just how that Hendrickson air ride front axle is designed.Thats why a lot of people don't like it.But the good part is that it absorbs a lot of vibration caused from bad roads and it rides much softer.It also helps extending the lifespan of your king pins.Good luck friend when I see you out there swerving left and right i won't be upset I'll know its you LOL

 

Sorry, English is not my first language,but I have good camera on my phone lool, ; soo i'll post photos to make myself understood with similar problems with my 780/2008 ;
-I replaced front springs twice in 1,3 mil miles, @ 6-700k and last month at 1,3 mil; they were not broken, but are getting weak;
-cab bushings;
-front airbags leaking and leveling valves;
This cab air ride valve caused my cab to move all over like drunk, see also the rod is setting the cab airbag height is made of cheap plastic ,breaks or jumps out, also the valve , bags and cab shocks;



- watch wearing in front hub/bearing ; my truck was shaking and I had vibrations all the way to steering wheel; I have this type, I hate this blind design, can't see if is any oil in the hub, or check it for metal shavings; my last Volvo 770 was a transparent plastic I could see it; this is the most dangerous bearing if goes dry;

 

CK. air bars at rear of sleeper, they have a cross bar that can give that feeling when worn?