Cat 345bl weak/slow

Hi guys...I have 1998 model S/N:4ss01099 cat 345bl excavator.It has very weak/slow hydraulic on all functions.Strange thing is that engine runs on load but all functions are too weak/slow.When i do any hydraulic function, engine runs on load but machine is too weak/slow.The tracks moves straight but it will not turn,boom can not lift up the machine,swing function is very very slow,stick and curl also similar.

thanks for input.

Cat 345bl weak/slow