I have a former Army machine with low hours. Everything works but the loader boom raise is extremely slow. It lowers fine, wonder if its a valve sticking or something else.
Something else. Gravity will make the bucket drop look normal. If you steer while working the loader does the steering become difficult? Backhoe cycle times good? Do you have gauges? If not the first thing I would be looking at is a defective destroke solenoid on the hydraulic pump. They can leak at higher pressures causing slow loader cycle times. I test them by removing them and installing a AR90378 plug ($28) . If your loader works fine with the plug installed then the solenoid is defective. If still slow then we will need to look elsewhere. Note that starting the engine could become more difficult with the plug installed.
Should be a priority valve for the loader function, might need adjusting or shimming to get the pressure up. Or the valve spool is not traveling as far as it's supposed to, have you checked the linkage from the control handle?