Opel 1900 1973 Service Manual page 376

MAIN DRIVE GEAR (INPUT)
COUNTERSHAFT GEAR UNIT 2nd SPEED GEAR
2nd SPEED GEAR
1st AND 2nd GEAR SLIDING GEAR
1st AND 2nd SPEED SLIDING GEAR GUIDE UNIT
Second Speed
After synchronizing the speeds of the mainshaft and
the 2nd speed gear, the 1st and 2nd gear sliding gear
shifts toward the front of the transmission and locks
the 2nd speed gear to the mainshaft through the 1st
and 2nd speed sliding gear guide unit. This 1st and
2nd speed sliding gear guide unit is internally splined
to the 1st and 2nd gear sliding gear and is externally
splined to the mainshaft. Both the 3rd speed gear and
the 1st speed gear are idling. The reverse idler gear
is not engaged with any gear and, therefore, it is
idle.
With a 2nd speed gear ratio of 2.156:1, the main
drive gear (input) must turn 2.156 revolutions for
every one revolution of the mainshaft (output).
POWER FLOW. 2nd SPEED
COUNTERSHAFT GEAR UNIT DRIVE GEAR
2nd SPEED GEAR
1st AND 2nd GEAR SLIDING GEAR
MAINSHAFT (OUTPUT)
Figure 78.3
MANUAL TRANSMISSION