2007 International 9400 rear suspension bottoming out

My driver told me a coupe days ago, the truck seemed to be starting to bottom out on big bumps and bridge separations, uneven roads. Now its doing it at every decent bump and bridge separations and such. Checked the bags, all are up, no leaks heard. The suspension seems to be riding where it needs to. Shocks aren't blown out, at least not leaking anyway. Cab bags are new and up. Any ideas?

 

Would it blow the air out that fast? Yes

 

I guess I made the assumption since the bags were up and full of air it wasn’t the leveling valve

 

The cab bags were full and up as well last evening when I looked. My driver said he’s definitely feeling it slamming but not in the front. And it just started happening gradual over the last 23 days

 

I’m taking it to our shop now. And I meant to say it started gradual over the last 2-3 days not 23 days.