transfercase and auxillary drives Flashcards
when would a transfer case be required
when operating in soft soil or off road and more traction is needed without adding more rear driving axles
why do most transfer cases use helical gearing
to handle the tremendous torque loads placed on them
how is the helical thrust load on a shaft offset
with tapered roller bearings
how many inputs and outputs do transfer cases have
one input and two output
how are most transfer cases lubricated
splash type with oil in a reservoir and can also have a positive displacement oil pump for areas where there is a speed difference such as PTO and front axle declutch
how is the internal oil pump driven
off the end of one of the shafts in the transfer case
what is the purpose of the front declutch
to allow the operator to disengage the torque to the front drive axle when ground conditions are good ( highway - dry even ground )
how is the front axle engaged
with a electric over air or air shift collar on a set of splines
on a short wheel based vehicle what drivetrain equipment is used to drive the front driving axle
a special inter-axle differential assembly
what is the function of the transfer case
the transfer case receives torque from the main auxiliary transmission . it then sends that torque on to the rear driving axles and forward to the front driving axle
what is the mechanism that gives the operator the ability to disengage the torque to the front drive axle
front axle declutch
what are the typical gear ranges for High and low with a transfer case with more than one gear range
high range is usually direct drive 1:1 while low range is usually 2:1 or 2.5:1 reduction
what device does a full time transfer case use to prevent driveline windup
a planetary gear set
can a transfer case mounted power take off receive more torque than the engine can develop
yes . because the power take off is mounted after the transmission it is able to receive varying amounts of torque . this is dependant on the gear selected in the main transmission
what could cause oil to be lost out the breather
if either the range shift cylinder, front axle declutch cylinder or power takeoff shift cylinder O-rings are leaking . the housing is put under excessive pressure and the rapid air venting can cause oil to be pulled out
what could cause excessive vibration in the transfer case
operating on good roads with the front axle declutch engaged . excessive driveline angles . excessive transfer case bearing endplay
one of the vital concerns with transfer case assembly is
bearing endplay
which types of auxiliary drive systems are always driving any time the engine is turning
front engine mounted and rear engine mounted
what must the operator do before engaging the power takeoff
stop the transmission counter shaft from turning
on the air actuated power takeoff system what is the air routed through before going to the air valve
the pressure protection valve
the indicator light for the power takeoff system is activated by what
a normally closed or normally open engagement switch mounted on the shift cover
what two functions do the gaskets between the power takeoff and the transmission provide
acts as a seal to prevent lubrication from leaking between the two components . provide a way of setting the proper backlash between the PTO input gear as well as between the adaptor housing gear and the PTO input gear
PTO gear backlash must be measured between
the PTO input gear and the transmission drive gear
when installing an adaptor housing what backlash must be adjusted
proper backlash must be established between the transmission drive gear and the adaptor housing as well as between the adaptor housing gear and the PTO input gear
if the power takeoff is installed with insufficient backlash what will the complaint be
gear whine
when reinstalling a repaired power takeoff is it acceptable to install without measuring backlash if the same number and thickness of gaskets are used
false . backlash must always be measured when installing
if the transfer case is a two speed or a single speed with a ratio other than direct drive where will the speedometer sensor be attached
to the rear output shaft of the transfer case .
why is the speed sensor mounted to the rear output shaft of the transfer case if it is a two or single speed with a ratio other than direct drive
this ensures that the vehicle speedometer and the engine and transmission ECU are always reading the correct vehicle speed
what is the proportion of torque delivered to the front and rear axels when utilizing a planetary gear set
front 30% and rear 70 %
when checking the oil level in the transfer case
the oil must be level with the bottom of the filler plug opening
what is one quick method of determining if the transfer case is damaged
by preforming a plug swap and inspecting the magnetic plug
