TROUBLESHOOTING SECTION IX Hard Shifting An   improperly   operating   clutch   will   interfere   with   the proper  shifting  of  gears  in  any  transmission.    It  is  also important    that    the    hydraulic,    air    or    similar    release mechanism   is   In   proper   working   order.      If   full   and complete   clutch   release   is   being   made,   the   following could  be  a  few  of  the  possible  causes  for  hard  shifting complaints: (a)   No   lubricant   in   remote   control   unit.      (Note   The forward  remote  is  isolated  and  is  often  overlooked. Many   remote   controls   used   on   transmissions   and auxiliaries require separate lubrication.) (b)   No   lubricant   in,   or   grease   fittings   on,   u-joints   or swivels of remote controls. (c)    Lack  of  lubricant  or  wrong  lubricant  used,  causing buildup,   of   sticky   varnish   and   sludge   deposits   on splines of shaft and gears. (d)   Badly worn or bent shift rods. (e)   Improper adjustment on shifter linkage. (f) Sliding clutch gears tight on splines of shaft. (g)   Clutch teeth burred over, chipped or badly mutilated because of improper shifting. (h)   Binding    or    interference    of    shift    lever    with    other objects  or  rods  inside  the  cab  or  near  the  remote control island. (i) Driver  not  familiar  with  proper  shifting  procedure  for the transmission, or with 2-speed axle or auxiliary. (j) Clutch  or  drive  gear  pilot  bearing  seized,  rough,  or dragging. (k)   Clutch brake engaging too soon when clutch pedal is depressed. (I) Wrong lubricant, especially if extreme pressure type lubricant is added. (m)  Free  running  gears  seized  or  galled  on  either  the thrust face or diameters. Sticking in Gear (a)   Clutch not releasing.  Also check remote  units  such as  hydraulic  or  air  assist.    Note:    On  some  units employing   a   full   air   control   for   clutch   release,   air pressure of approximately 60 lbs.  or more  must  be secured before the clutch can be released.   Do not leave these vehicles parked in gear. (b)   Sliding clutch gears tight on splines. (c)    Chips wedged between or under splines of shaft and gear. (d)   Improper adjustment, excessive wear or  lost  motion in shifter linkage (e)   Clutch  brake  set  too  high  on  clutch  pedal,  locking gears behind hopping guards. Bearing Failures The    service    life    of    most    transmissions,    main    and auxiliary,  is  governed  by  the  life  of  the  bearings.    The majority of bearing failures can be attributed to vibration and dirt.  Some other prominent reasons for unit bearing failures are: (a)   Fatigue of raceways or balls. (b)   Wrong type or grade of lubricant. (c)    Lack of lubricant. (d)   Broken retainers, brinelled races and fretting caused by vibration. (e)   Bearings set up too tight or too loose. (f) Improper installation resulting in brinelled bearings. (g)   Improper fit of shafts or bore. (h)   Acid etching due to water in lube. (i) Vehicle   overload   or   too   large   an   engine   for   the transmission resulting in overload. Dirt More than 90% of all ball bearing failures are caused by dirt, which is always abrasive. Dirt may enter the bearings during assembly of units, or may be carried into the bearing by the lubricant while in service.  Dirt also may enter bearings through seals, the breather  or  even  dirty  containers  used  for  addition  or change of lubricant. Softer   material,   such   as   dirt   or   dust,   usually   forms abrasive     paste     or     lapping     compounds within the bearings.  The pressure between the balls and raceways makes  a  perfect  pulverizer:  The  rolling  motion  tends  to entrap    and    hold    the    abrasives.        As    the    balls    and raceways wear, the bearings become noisy.  The lapping action tends to increase rapidly as the fine steel from the balls and rollway adds to the lapping material. Hard,  coarse  material,  such  as  metal  chips,  may  enter the    bearings    during    assembly    from    tools    such    as hammers,   drifts,   and   power   chisels.      It   may   also   be manufactured  within  the  unit  during  service  from  raking teeth.    These  chips  produce  small  indentations  in  balls and races.  When these hard particles jam between the balls  and  races,  it  may  cause  the  inner  race  to  turn  on the shaft, or the outer race to turn In the housing. Fatigue All bearings are subject to fatigue and must be replaced eventually.  Your own operating  experience.    will  dictate mileage  replacement  of  bearings  showing  only  normal wear. 27