I have a old backhoe just change seals and injectors on the Engine works fine no the issue strugles to lift backhoe, front bucket and legs..when activating the valves for any hydraulic action makes noise on poor hydraulic lift then engine ratles.. It seem are hydraulic lines dirty or poor returns,, any idea what's wrong will greatly appreciated.. thank you for reading my issue.. Mt Trejo
Your description of the noise indicates that the hydraulic oil in its reservoir is very low. Air in the system vibrations and growling noises.
Check the quick couplers at the backhoe, make sure they are connected properly.