The link works directly for me. Try https://www.nicoclub.com/infiniti-service-manuals
and then go to the model/year of your car and open the at.pdf file
This may not be a problem with the actual solenoid. It's turned ON and OFF by the TCM in response to signals from the PNP switch, vehicle speed sensor and accelerator pedal position sensor. The first step is to validate the harness and connectors. I would go through the above FSM and validate each of those components are outputting the proper signals and they are being received properly as well. If the components of the valve body were not the actual problem then replacing it won't solve the problem.