With just 3-4 graduations, no damping and low fluid is safe to say your globes are gone and full of the missing fluid. With new globes, a proper fluid exchange to get rid of the old gassy contaminated stuff and setting your neutral pressures up you’ll have a new ride. You can combine the fluid changeout with your new globe installation to kill two birds with one stone, nice and easy.
From what I’ve gathered so far, looks like I should drop the truck to Lo then siphone out whatever fluid is left in the res and dump a whole 2.5qts can of ahc fluid into the res and then open the bleeder on all 4 corners. Then just unscrew the globes and put in new ones? I do not know how to set neutral pressure and I do not have techstream at the moment. I’ll have to check and see if my $4000 matco scanner at work has ahc stuff on it.