same the pressure at the clutch 54 begins to rise quickly as controlled by the control system 44 and finally settles down around the value of 52 during the clutch fill process the relationship between the lines 50 and 54 should be noted during the clutch fill phase the pump 30 which is usually flow limited will be unable to maintain the same line pressure and the high flow requirement at the same time as a result there is a temporary drop in system line pressure 50 during the clutch fill phase as this initial volume flow into the clutch cylinder 18 subsides at the end of the clutch fill phase and the pressure begins to build toward full clutch engagement pressure the line pressure sensed by the pressure sensor 40 begins to return to a nominal operating pressure this return to the nominal operating pressure precedes full pressure in the clutch cylinder 18 and full engagement of the friction clutch pack 24 of the clutch assembly 16 referring now to fig1 and 3 an algorithm which can be embodied in the software of a microprocessor of the transmission control module 42 or the clutch pressure control system 44 is illustrated and designated by the reference number 60 the software algorithm 60 begins with a start or initializing step 62 which is commenced upon a clutch fill command or instruction from the transmission control.