A friend had some service work done to the hydraulic pump and control valve of his 2305. After the work the hoe attachment will not operate properly. It appears that flow is improper as the hydraulics will only operate in one direction when the control valve is actuated and tractor is running. When tractor is off alternate direction flow is possible. I am concerned the pipe port plug was not reinstalled in the port on the front of the rock shaft valve under the seat. Does anyone know if this is a possible diagnosis for the condition I have described? Thanks for any advice.