2017 cottrell cx09 80 footer, wont lift a 2500 or f250

Yes, air can cause chattering of the cylinder or valve body. Not lifting a load all the way is typical for a low fluid level or air in the system.
Sounds like your fluid needs to be changed though I don't think that alone will solve your problem.
Check without a load for anything bent or binding and grease/lube any pivot points. You could then change/flush the fluid and bleed. If that does not solve the problem then someone will need to hook up some pressure gauges and see what they read.

Below are 2 links, some of which I already stated.

What Causes a Hydraulic Cylinder to Chatter? - Cylinders, Inc.
Hydraulic Fluid Colors: Quick Guide for Maintenance Pros

 

30 years working on carhaulers and the best fabricator I know of said.
“Anytime you have chattering of a valve bank it’s usually a good indication that the springs inside of that bank are getting weak. The chattering is usually the ball valve bouncing up and down”

 

I would just order a couple new valves and move on with it. East Coast is actually easier to deal with than Cottrell unless you are close enough to stop by Cottrell.

 

I guess it depends on if it keeps you from working. Those cylinders aren’t expensive and downtime is.
You could buy them and see if the other repair works before you install them. You likely could need them to eventually.

 

I would start by installing a tee and a pressure gauge where the hose for the pump hooks up. That is the LH side.
3000 PSI min.