Mahindra erratic hydraulics

[Wyld Bill]

Hey guys I really need your help.
I have a 2004 Mahindra 2615 hydrostatic tractor.
This past summer I let a buddy of mine borrow it (first mistake I know)
While he had it the ailing bucket control valve finally failed completely.
So he marked all the hose connections, removed the hoses, spilled a bunch of hydro fluid on the ground, installed a new control valve, and added Mahindra hydraulic fluid to top it off.
I got the tractor back in late fall and noticed the hydraulics were a bit "jerky"
I didn't use the tractor much until we started getting snow. I changed all of the hydro filters.
Now I'm noticing a real problem with the tractor.
There is a lot of hesitation in the hydraulics. I mostly notice it in the FEL use but some times in the steering too.
It's like a surge, hesitation, accompanied by a noise like "dut, dutttutut" as it is "fetching up"
So could it be that he mixed Mahindra fluid with the John Deere fluid I had in there?
Did he get dirt in the system and ruined the pump?
Could the hoses be hooked up wrong some how?
Am I sucking air???

 

[Looking4new]

I would say you got air in the system. But I am no expert on hydraulics.

 

[J_J]

Check fluid level.

Do you have any bubbles in the reservoir?

You perhaps have some air in the hyd system, plus maybe some water.

Cycle the loader many times, about 10 complete cycles.

Do a crackle test where you heat up a spool of your hyd fluid and see if it crackles or sizzles.