2005 chevy silverado 4wd problems

[david8465]

Hi everyone,

I took my truck to the dealership and had these codes pulled: C0306, C0321, C0327 and C0379. Tech told me my encoder motor needs replacing for $700. I replaced it with an after market unit bought through monster autoparts. At first after installing the new unit the selector switch light lit up properly and I could select between A4WD 2HI 4HI and 4LO but the front axle would not engage. Now the selector switch is stuck lit on A4WD and will not change. The encoder motor makes a cycling noise like it is trying to shift between gears with the key off and out of the ignition. (does it also with the engine running) The front axle actuator will lock the front axle. Anyone have this problem? This drive 4wd system ihas been an absolute pain. any ideas? Any suggestions would be appreciated.

[MT-2500]

Originally Posted by david8465

Hi everyone,

I took my truck to the dealership and had these codes pulled: C0306, C0321, C0327 and C0379. Tech told me my encoder motor needs replacing for $700. I replaced it with an after market unit bought through monster autoparts. At first after installing the new unit the selector switch light lit up properly and I could select between A4WD 2HI 4HI and 4LO but the front axle would not engage. Now the selector switch is stuck lit on A4WD and will not change. The encoder motor makes a cycling noise like it is trying to shift between gears with the key off and out of the ignition. (does it also with the engine running) The front axle actuator will lock the front axle. Anyone have this problem? This drive 4wd system ihas been an absolute pain. any ideas? Any suggestions would be appreciated.

To many codes.
With that many cods could be transfer case computer or wiring.

What Silverado and what transfer case?
Were codes cleared and retested.
For what code popped first.
Clear codes and see what code comes back first.

To test and repair transfer case problems you will need a good transfer case scanner and some good repair info on the repair flow charts.

Not just throwing parts at it from somebodys code check.

[j cAT]

what is the transfercase fluid color ?

[david8465]

the blue stuff, cant think of the name of it. replaced it 18 months ago. looks good

[david8465]

05 Z71 LS trim package with 5.3. the transfer case is NG-246. the service 4wd no longer pops up on the DIC with the new encoder motor on it, but does feel like the front actuator is engaged when turning. I havent cleared the codes. How is this done? Once I figure out how to clear the codes I will wait and see which codes pop up first. I did pull the 4wd fuse in the dash fuse panel and the trec fuse in the engine compartment fuse panel to stop the motor from buzzing/cycling.

[j cAT]

it is possible that the encoder is not installed correctly or is defective. many have installed these wrong or had defective part. remove encoder and check for proper alignment to the engaging fork.

when this is being done recheck the wiring especially the smaller sensing wirings to report encoder position.

with one front wheel off the ground see if you can rotate it. if not the front locking actuator is locking the front axle together .

if the fluid now is still blue then there is a very good chance this is an electrical issue.