2011 ProStar cab shocks shot at 300k

This truck is beating me to death.
The cab shocks bottom out no matter how the ride height is adjusted.
I can bounce the cab real easy with one hand.

One of our other trucks is the same way.
We compared it to a new truck and the new truck had very little give to them.

Shop wants 1000 bucks just for parts! So the boss said no way.

Is this common with these over priced cab shocks?

 

Thanks guys! The shock is inside the airbag on these....Not the normal airbag with a shock mounted next to it.
The right front cab mount shows signs of the rubber bushing cracking.
The cab wobbles and bounces so much it is eating the fiberglass of the edge of my hood above the hood latch on one side.
I get sore really fast compared to the way it used to drive.

 

Wow...Monroe makes them....164 bucks each!

http://www.amazon.com/gp/product/images/B001IA9HIM/ref=dp_image_z_0?ie=UTF8&n=15684181&s=automotive

 

Thanks for looking into it Heavyd,

The roads around here are not too bad.
It is just strange my truck and one other started riding bad around the same mileage....the 300k range.

The shop replaced his and there is a huge difference....Mine rocks like crazy if sit down in the bunk or grab the back of the cab from outside.
I can feel mine bottom out on the highway and the constant rocking up and down while driving.

The air adjustment and ride height are normal when parked..