Selectable Four Wheel Drive (S4WD) Front Axle Description and Operation
The Selectable Four Wheel Drive (S4WD) Front Axle consist of the following
components:
|     •  | Differential Carrier Housing | 
 
|     •  | Differential Case Assembly | 
 
|     •  | Intermediate Shaft Bearing  Assembly (located on the right side
of the oil pan) | 
 
|     •  | Electric Motor Actuator | 
 
The front axle on Selectable Four Wheel Drive (S4WD) model vehicles
uses a disconnect feature mounted on the right side of the oil pan in order
    to engage and disengage the front axle.  When the driver engages the 4WD
   system,  the Transfer Case Control Module sends  a signal to the electric
   motor actuator  to energize and extend the plunger  inside. The extended
  plunger  moves the  clutch fork and clutch fork sleeve  across from the
clutch   fork outer  gear that  is splined to the right side wheel drive shaft
to  the  clutch fork  inner gear  that is splined to the inner axle shaft.
The  locking  of the two  gears allows  the axle to operate in the  same manner
 as a semi-floating   rear axle. A propeller  shaft connects the transfer
  case to the front axle.   The differential carrier  assembly uses a conventional
  ring and pinion gear   set to  transmit the driving  force of the engine
 to the  wheels. The open   differential  allows the wheels  to turn at different
 rates  of speed while   the axle continues  to transmit  the driving force.
 This prevents  tire scuffing   when going around  corners  and premature
wear  on internal axle  parts. The   ring and pinion set  and the  differential
 are contained within  the carrier.   The axle identification  number  is
located  on top of the differential  carrier   assembly or on a label on the
 bottom  of the right  half of differential    carrier assembly. The wheel
drive  shafts  are completely flexible  assemblies   consisting  of inner
and outer  constant  velocity CV joints protected  by   thermoplastic  boots
and connected  by  a wheel drive shaft. 
Automatic Four Wheel Drive (A4WD) Front Axle Description and Operation
The Automatic Four Wheel Drive (A4WD) Front Axle consist of the following
components: 
|     •  | Differential Carrier Housing | 
 
|     •  | Differential Case Assembly | 
 
|     •  | Intermediate Shaft bearing  Assembly (located on the right side
of the oil pan) | 
 
The front axle on Automatic Four Wheel Drive (A4WD) model vehicles do
not have a disconnect feature in order to engage and disengage the     front
 axle. The Automatic Four Wheel Drive system uses the same differential  
  carrier assembly and intermediate shaft bearing  assembly, but the clutch
fork,   the  clutch  fork sleeve and the inner/outer gears have been replaced
with   a single  splined  sleeve that connects the inner axle shaft directly
to  the  right side wheel  drive  shaft. This connection allows the right
side wheel drive  shaft  and the intermediate   axle shaft to be directly
connected to the differential   case assembly. It   also results in having
the wheel drive shafts, the intermediate   axle shaft   and the propeller
shaft to spin  continuously. When the transfer   case is  active,  the clutch
assembly within the transfer case controls the   amount  of torque  applied
to the  front axle. The remaining components are   the same  as the selectable
 four wheel  drive axle.