Jun 022016
 

2002 Chevy SilveradoWhen my 2002 Cheverolet Silverado 1500 4WD Ext Cab LS is moving the front end rattle badly. When i put in 4wd the rattle is quite a bit quieter however the 4wd does not engage it just makes a clicking sound.  I Know the front end is out of alignment and needs to be realigned , but the rattle noise and 4wd malfunction is new. What could be the problem or problems?


RESPONSE

There are many possibilities when it comes to a rattle noise or any noise for that mater. Could be something loose or worn. A hub bearing assembly going out could be at fault. Maybe an axle-shaft or universal joint going bad. Could be internal in the front differential. Possible 4WD actuator issue.

Rattle in front end

Front Drive Axle Description and Operation

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 Assembly
    • Output Shafts (Left and Right Side)
    • Inner Axle Shaft Housing
    • Inner Axle Shaft (Right Side)
    • Clutch Fork
    • Clutch Fork Sleeve
    • 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
    • Differential Assembly
    • 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.

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