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 | 
 
|     •  | Output Shafts (Left and Right Side) | 
 
|     •  | Inner Axle Shaft Housing | 
 
|     •  | Inner Axle Shaft (Right Side) | 
 
|     •  | Electric Motor Actuator | 
 
The front axle on Selectable Four Wheel Drive model vehicles uses a
central disconnect feature 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 the inner axle shaft and the clutch fork shaft and locks the
two shafts  together. The locking of the two shafts 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 drive axles are completely
flexible  assemblies consisting  of inner and outer constant velocity CV joints
protected  by thermoplastic  boots and connected by a wheel drive shaft. 
Full-Time Four Wheel Drive (F4WD) Front Axle Description and Operation
The Full-Time Four Wheel Drive (F4WD) Front Axle consist of the following
components: 
|     •  | Differential Carrier Housing | 
 
|     •  | Output Shaft (Left Side) | 
 
|     •  | Inner Axle Shaft Housing | 
 
|     •  | Inner Axle Shaft (Right Side) | 
 
The front axle on Full-Time Four Wheel Drive model vehicles does not
have a central disconnect feature in order to engage and disengage the front
 axle. The left and right axle shafts are connected directly to the differential
 case assembly. This allows the axle shafts and the propeller shaft to spin
 continuously. 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.