Something is making my Cascadia move at night when i'm in sleeper

It's losing air BUT it doesn't have to be the air bags... alot of things can make it lose air the bags deflate because the system air pressure goes down....

What's your air pressure read before you start it in the morning....?

 

For me it's not an overnight thing. Out flats dump air almost immediately so if you set the trailer and truck together it'll eventually jump. I make a habit of waiting 20 seconds before setting the truck brakes for this reason.

 

Probably the leveling valve, if it’s intermittent. Or maybe the shop was warmer than when you usually notice it. Some leaks will only show up when cold. The big jolt, is worse when fifth wheel is sloppy, or dry. Also when driveshaft slip yoke is dry, and binds up. Yeah, right before you fall asleep, usually, feels like someone ran into the back of your trailer. I’m like WTF? Lol.

 

Sometimes you can get spring recoil. This happens from time to time with my single axle flat bed with spring suspension. After I back up and hit brakes to stop the tractor may continue to back into trailer tighter causing the springs to bind up a little. If you immediately set parking brakes without releasing the foot peddle to allow everthing to stretch back out it will stay bunched up under a load until the air springs lose a little pressure or the parking brakes are released whatever comes first. It will feel like a jolt sometimes. Also happens when you park tight on a dock too.