4WD problem

Tiny
EGUNS80
  • MEMBER
  • 2003 GMC ENVOY
  • 4.2L
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
I had my truck on the lift earlier to check my 4wd, when I switch the indicator to 4H it sounds like it is engaging, but it is not and there is a slight clicking sound coming from my transfer case. What could be the problem?
Wednesday, May 8th, 2019 AT 6:14 PM

3 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Hi Eguns80,

I attached the description of your transfer case. If it is not engaging then I would expect the clicking is coming from the encoder motor trying to turn the actuator but it is not able to. So it is either the motor or this assembly. The best way to figure it out is get in there and monitor the operation. I included the procedure for replacing the encoder actuator which will get you into the entire system.

Unfortunately, there are no magic bullets for this one. You will just need to test the motor and then inspect the actuator and lever to see if it is able to move.

Read this over and let me know if you have questions. Thanks
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Wednesday, May 8th, 2019 AT 7:09 PM
Tiny
EGUNS80
  • MEMBER
  • 78 POSTS
The clicking is happening after I put it in gear while the rear wheels are spinning and the front should be spinning. Sorry forgot to add that.
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Thursday, May 9th, 2019 AT 12:38 AM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Okay. If you hear the clicking but it is not engaging the front wheels, this could still be the actuator or it is potentially the clutches not fulling engaging. If you look at the first attachment from my last post, you will see the power flow when in 4HI. The only thing different from 2WD to 4HI is the clutch lever applies the clutches which directs power through the case to the front. No gear reduction is happening so it appears it is in the engagement system or the clutches themselves.

If this doesn't make sense, it may be needed to send a video or audio recording over so I can hear it. Maybe we just aren't talking about the same thing because I am envisioning a noise that this is not making.
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Thursday, May 9th, 2019 AT 12:04 PM

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