jd 710b hydraulic issue

1983 jd710b backhoe/loader. all the hydraulics move and work. they also speed up with engine speed. pump was making noise so took that off and had it rebuilt. ive checked the screen and put new fluid in tranny. put a new hydraulic filter on and check the rubber piece between crank and pump. everything is good. put new pump back in yesterday and the problem still is when i go to use the loader or backhoe or side posts, they will go up and down but when i go to actually use it like for it to lift machine up or work, it just gives out. it will lift itself right back up but will not allow to put any load on it and motor does not grunt. so i cant use the loader really and really cannot use the backhoe.



is it a priority valve? i dont know what else to check? i have service manual.

jd 710b hydraulic issue