John deere 3040 Hydraulic Pump NOISE! Need Tips!

Описание: Open to all suggestions for a solution to this noise.

I have some problems with noise from the hydraulic pump. When it is cold (comes after 10min) there is no sound. The hydraulics are also pulsating but this has been ok lately. Looks like this is a common JD problem as I find a lot of info online but rarely does it end up with a solution. The oil is new, all filters and the "long pipe" (screen?) at the bottom are new. This summer, when it was hot and the tractor had been running all day, the lamp for hydraulic pressure began to light up, the pressure was so low that I had problems using the hydraulics. This only happens when the tractor is very hot, not when used for less than 1-2 hours.