The auxiliary hydraulic control should be the middle pedal on the 610 I think.Is your aux hydraulics stuck on? it should be the right steering stick, pull it to the left, then let it spring back to neutral.
If thats not it, it could be your relief valve, it may have something stuck in it preventing you getting any pressure.
Have you checked the oil level in the chain case? That is your hyd reservoir also and after 2 years may be low. Two little pipe plugs on the left outside of the chain case. one for high, one for low level.The auxiliary hydraulic control should be the middle pedal on the 610 I think.