4X4 not engaging

Tiny
BIGREDZ
  • MEMBER
  • 2002 CHEVROLET AVALANCHE
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 200,000 MILES
Hi guys, I have read up on your message boards and still am perplexed with my four-wheel-drive. 4 x 4 and ATC fuses are good, the switch and lights seem to operate properly but when I switch into four high or four Lo the transfer case engages but the front differential does not, even though the switch and lights say it has switched into four-wheel-drive.I’m looking at the front actuator next, and the encoder motor control. Do you think it could be anything else?
Monday, February 24th, 2020 AT 5:59 PM

4 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,874 POSTS
Hi,

Chances are the front electric actuator motor on the axle is bad. Before replacing it, confirm there is power to it. If there is power and it doesn't respond, replace it. If there is no power, then suspect the encoder. Please keep in mind, there is most likely a diagnostic trouble code stored in the computer related to the issue. You may want to have the computer scanned with a scanner capable of reading such codes.

_____________________________

Here are a few links you may find helpful when testing:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

____________________________

2002 Chevy Truck Avalanche 1500 4WD V8-5.3L VIN T
Electric Motor Actuator Replacement
Vehicle Transmission and Drivetrain Differential Assembly Service and Repair Procedures Front Drive Axle Electric Motor Actuator Replacement
ELECTRIC MOTOR ACTUATOR REPLACEMENT
Electric Motor Actuator Replacement

Removal Procedure

pic 1

1. Raise the vehicle. Refer to Vehicle Lifting.
2. Remove the front differential carrier shield, if equipped.
3. Disconnect the electrical connector from the actuator (3).
4. Remove the electric motor actuator (3) by turning the actuator counterclockwise.

Installation Procedure

pic 2

1. Apply sealant GM P/N 12346004 (Canadian P/N 10953480) to the threads of the electric motor actuator.

Notice: Refer to Fastener Notice in Service Precautions.

2. Install the electric motor actuator (3).
Tighten the actuator to 20 Nm (15 lb ft).
3. Connect the electrical connector to the actuator.
4. Install the front differential carrier shield, if equipped.
5. Lower the vehicle.

______________________________-

Let me know if this helps.

Take care,
Joe
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Monday, February 24th, 2020 AT 6:29 PM
Tiny
BIGREDZ
  • MEMBER
  • 3 POSTS
I will check it out tomorrow and let you know. Thanks Joe.
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Monday, February 24th, 2020 AT 10:33 PM
Tiny
BIGREDZ
  • MEMBER
  • 3 POSTS
I took it to a shop where I was having my brakes done, and ask them to check out It out and they found the transfer case and front actuator and both had power and functioning. The only other thing they said it could be is that the actuator fork is broken off, or I have some front differential issues. I’ll be taking off the skid plate and Front actuator this weekend to narrow it down a bit.
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Tuesday, February 25th, 2020 AT 11:48 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,874 POSTS
It could be the fork, if the actuator is working. Keep in mind it is an electric motor. It could have power and not run.

Let me know what you find.

Joe
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Tuesday, February 25th, 2020 AT 6:42 PM

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