I have a kubota L345dt . I had the gear and needle bearing go out to the drop box. The hydraulics got contaminated with gear dust or bearing dust and metallic with fluid. I cleaned the hydraulic system out when I split the tractor apart. When this bearing started going out my hydraulic loader had a very hard time going up and won't lift hardly any weight. The loader works off of the tractors hydraulics. The three point hitch and all the other hydraulics work fine. I checked the relief valve, put a gage on port 32 to check the hydraulic pressure, only getting 500-600psi at a high rpm. Do you think this could be the hydraulic pump? Or what else can I check?