Deere 310D Backhoe transmission

[jayguy]

Hello all. I have an issue with my fathers backhoe slipping out of gear. Some days it has no problems, but then others like today,I can't get it to move. I checked the fluid, and for starters, there is way too much. I can't fault him much as for he is 86 and can still run circles around me...
I also found out that he used regular hydraulic fluid instead of oil when he put it in.

My issue is, if I were to change all of the oils and filters, would it be possible that it might fix the problem?

 

[Tx Jim]

Changing to the correct hyd oil along with new hyd filters and checking sump screen would be a step in the right direction.