Can anyone tell me which line on the P7100 is the return line? I have cut the line coming off the top of the filter housing to connect it to a solenoid valve, and must cut the return to send it to either the grease loop or the diesel tank and want to make sure I cut the right one. There are two lines that look like they are both connected by banjo fitting to the supply one in the front of the pump and one in the back. I only see two other lines which look like they may be oil lines. Appreciate any help with this.