Confused about boost valve and reverse boost valve
 

Reverse is slipping. New clutches were installed not to long ago. Fluid dark but not really dark. I tried the Lucas and no help. I don't have a line pressure gauge to test pressures. Where is the reverse boost valve or is the boost valve also called the reverse boost valve? I can take the clip off the EPC and remove it, however there is a clip holding the pins in and it is installed between the valve body and the separator plate. Should the clip be there at all? Would it help the slipping situation to remove the check ball from the capsule at the rear under the separator plate?
http://i1137.photobucket.com/albums/.../Valvebody.jpg