respectively to directions toward and away from the geometric center of the device and designated parts thereof said terminology includes the words above specifically mentioned derivatives thereof and words of similar import the term u201c compound transmission u201d is used to designate a change speed or change gear transmission having a main transmission section and an auxiliary drive train unit such as an auxiliary transmission section connected in series whereby the selected gear reduction in the main transmission section may be compounded by further selected gear reduction in the auxiliary transmission section the term u201c upshift u201d as used herein shall mean the shifting from a lower speed gear ratio to a higher speed gear ratio and the term u201c downshift u201d as used herein shall mean the shifting from a higher speed gear ratio to a lower speed gear ratio the terms u201c low speed gear u201d or u201c low gear u201d as used herein shall designate a gear utilized for relatively low forward speed operation in a transmission i e a set of gears having a higher ratio of reduction of output shaft speed relative to the speed of the input shaft u201c synchronized clutch assembly u201d and words of similar import shall designate a clutch assembly utilized to non rotatably couple a selected gear to a shaft by means of a positive clutch in which attempted engagement of said clutch is.