GENERAL SECTION I INFORMATION OPERATION Replacement Parts The exploded views of subassemblies incorporated here are   for   the   mechanic’s   convenience.      The   parts   are arranged  in  their  correct  order  and  may  be  used  as  a reference for the assembly or disassembly of this unit. Synchronizer Information The    purpose    of    a    synchronized    transmission    is    to simplify  shifting  and  to  help  the  driver  get  a  clash  free shift.  To receive these results, however, It is important to under- stand how the synchronizer works. When  a  shift  is  required,  the  operator  declutches  and moves the shift lever toward the desired gear.  When the synchronizer   ring   makes   contact   with   the   gear,    the blockers    automatically    prevent    the    shift    collar    from completing the shift until the gear and mainshaft speeds are   matched.      At   that   time,   the   blocker   automatically neutralizes.    The  lever  moves  smoothly  and  easily  into gear. It  takes  one  or  two  seconds  to  match  speeds.    Steady pressure on the shift lever helps the  synchronizer  do  its job quickly If the lever is "forced" into gear, it is possible to  override  a  blocker.    This  defeats  the  purpose  of  the synchronizer, however, and can cause gear clash. Finally, remember that this transmission is not synchronized  in  first  and  reverse  gears  because  these gears    are    normally    selected     when     the     vehicle     is stationary.    No  synchronizing  of  engine  speed  and  road speed is required to get in gear from a stop. Caution: Always start in first gear.  Starting in any other   gear   may   cause   hard   shifting   and   internal transmission damage. This is because a synchronizer needs gear rotation to do its job. Driver Instructions To  begin  shifting,  first  depress  the  clutch  and  wait  for complete  release.    Move  the  shift  lever  into  1  st  gear. Next,   accelerate   to   an   RPM   that   will   allow   enough momentum   to   select   the   next   higher   gear   while   still allowing   vehicle   acceleration   after   the   shift   has   been completed.  (There is usually no reason to go all the way to     the     governor     before     you     shift     to     second.)The progressive shift technique helps save fuel.  This method can  vary  depending  on  the  GVW  of  the  vehicle,  road condition and type of service. When 2nd gear is desired.  declutch and move the lever toward  2nd,  keeping  steady  pressure  on  the  lever  The synchronizer  will  pick  up  the  gear  and  synchronize  its speed to the mainshaft speed.  The lever will move into gear easily. Continue in the same manner to top road speed.  Notice that to have good performance as you approach top road speed,   you   must   accelerate   closer   to   the   governed speed  before  you  allow  the  engine  to  drop  to  the  next gear shift point.  This is because air resistance at higher speeds     requires     more     horsepower.          You     receive maximum   horsepower   and   performance   at   governed speed. When you downshift, use the same procedure. However,  the  engine  must  be  raised  to  the  governor  as the   clutch   is   engaged   after   completing   the   shift.      To downshift  from  top  gear,  declutch  as  you  approach  the shift  point  (the  shift  usually  starts  about  100  RPM  over the  shift  point),  and  move  the  shift  lever  with  a  steady even  pressure  toward  4th  gear.    The  synchronizer  will pick   up   4th   gear   and   speed   it   up   to   vehicle   speed, allowing a clash free shift.  After the shift, re-engage the clutch  while  accelerating  to  keep  the  vehicle  moving  at the  desired  speed.    If  further  downshifts  are  required, continue in the same manner. When   downshifting,   remember   that   1   st   gear   is   not synchronized.  Double clutching is required to complete a clash free shift.  You can double clutch on all other shifts as well.  This only aids the synchronizer in doing  Its  lob by manually helping to match the engine speed and road speed. Caution: Do    not    tow    vehicles    equipped    with Spicer  transmissions  without  first  pulling  the  axle shafts  or  disconnecting  the  driveshaft.    Lubrication of   the   internal   gear   train   is   inadequate   when   the vehicle   is   towed.      Also,   do   not   pull   or   roll   start vehicles in first or reverse gears. 3