Questions about pusher axles

All of our 4 axle trucks run twisty knob regulator valves. And if we ever run California we just don't even use it.

Our older trucks even with the regulator, the guys in the shop had to shim them up quite a bit to get enough pressure to take the weight. These are the trucks where The Pusher axle raises a good three to four inches from the ground.

The newer trucks use a different air bag that extents farther. And we have found that we need to run more pressure in these to take the weight and not cause tire hop during hard braking. The tire hop is probably also caused by the fact that we run drum brakes on the pushers and disc on the others. My current truck has this system and I run 20 lb over what I have in my drives.

 

With the short neck and slid back fifth wheel as well as the 60” spread I’m kinda surprised you had 11k on the steer.

 

Shimming the bags may not fix the problem.
Your problem is likely the difference is suspension geometry and/or bag size from you drive axles and you pusher. Only easy way to fix that is to have more pressure on your pusher axle bags.