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2003 gmc envoy_slt_xl
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170 Posts
:thumbsup: Great work linn - I had little to do with it - it was your courage to start the job man - that is the hardest part - once you're knee deep you got to finish....

It does not matter how long it lasts... what you now know, is, it is not that hard to take apart and put back together ... and you have super access to all the tools... you are well on your way to dealer freedom LOL....

I must admit it was real cool to go through the drive switch positions and have it work. Congratulations on rising to the challenge.... :thumbsup:
 

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2005 chevy trailblazer_lt_ext
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2 Posts
HELP: 2005 Trailblazer xlt lt 4x4 I6 clicking in front driver side

:bonk: hello! I have a trailblazer that when im stuck and need to get out of driveway and i go to lock it in any 4wd setting, It clicks in the left front sounds like in the axle ( no play in axles) front end somewhere deff drivers side. But if im moving say im pulling into my driveway with lots and lots of snow, i lock it into any 4wd setting its fine no clicking or anything it works perfect. Just when im at a stand still and i try to lock in any 4wd setting it acts like it is under stress and i hear the clicking. The back tires will move but front ones will not,but if i can get the truck to rock back and forth it will lock in. Does this sound like an internal spline issue? Or maybe could it be a bad accuator on drivers side? the clicking kinda sounds like a cars bad cv joint sorta... Thanks hope to hear from you soon as i would like to be riding on the beach/mudding right now!! :thx
 

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2004 gmc
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26,181 Posts
A bad actuator will announce its failure by blinking the light on the mode switch over the mode you're trying to switch TO.

If you don't get blinking lights, your problem is mechanical, and statistically, most likely to be a bad splined disconnect on the passenger side of the oil pan.

http://www.offroadtb.com/articles/tech-docs/front-axle-4wd-disconnect

I assume you've already checked the differential oil level on the driver's side?
 

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2003 gmc envoy_slt_xl
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325 Posts
Discussion Starter #44
If you just read through this thread you are on and use the link above that Roadie gave, you will be on the right track to diagnose. Probably you have some parts in the disconnect (under front passenger's feet on right of oil pan connected to front axle) that are worn and need to be replaced so that it engages better.

That clicking sound you refer to, I had it as well, and it was definitely coming from the disconnect which I took apart and repaired. It my case, though, it never engaged. In your case it sounds like it is engaging some of the time.
 

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2003 chevy trailblazer_lt_ext
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7 Posts
03 Trlaiblazer R front axle is free from the differential

Good evening,

Please forgive my ignorance in the following description...

After putting the truck on a lift I have discovered that the front right(passenger side) bearing is shot. This is where the front axle goes into the front differential. I can actually lift the axle and look inside the differential.

Ok, I get it. I absolutely missed all the warning signs and so did the local mechanic. A while ago, I thought I was leaking motor oil but this turned out to be the differential oil. Yes, lots of noises, replaces rotors, brakes, tir rods, inner & outer, etc. Completely missed it..... :(

Oh well, water under the bridge. So, the task at hand it is to either replace the front diff with a rebuild and maybe front right axle, or refurbish the front diff and axle.

I was quoted $3200 for the refurb from the local mechanic or I can take it to the local do it yourself garage. Nice, fully furnished with everything plus good mechanics for advice or hands on help.

I would think that the rebuild is all set and simple requires the tear out and reinstall. I am sure that this is quite a job. Or, refurb the diff which I am sure is even more complex.

Bearing refurb kits are about $130 and a rebuilt diff is aroud $625 with a return of the core.

I am pretty handy with tools but, I think I am in over my head....

Your opinions gents? :undecided
 

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2004 gmc
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26,181 Posts
The front differential is on the driver's side. :weird:

Passenger side is called the splined disconnect. Time for your mechanic to join trailvoy or buy a manual. :hopeless
 

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2004 chevy trailblazer_ls
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8 Posts
Service 4DW Light is on.

:crazy: My light just came on the other day. I have not used the 4WD since March.
Why would the light come on now? The lights on the switch are not lit either.

It has done this before but then it eventually went back to normal.

What do I need to do to fix this??

Thanks
 

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2004 gmc
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26,181 Posts
Any time the PCM cannot communicate to the TCCM, the Service 4WD light on the dash goes on. If the lights on the mode selector switch are out, then the TCCM is asleep or not getting power. You need to start troubleshooting it by testing the TCCM fuse mentioned in other threads discussing TCCM problems (not this one). Then pull the fuse to attempt a TCCM reset.

If you had a buddy to trade TCCMs with, it would go a lot faster than shotgunning it.
 

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2005 gmc envoy_slt_xl
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40 Posts
A bad actuator will announce its failure by blinking the light on the mode switch over the mode you're trying to switch TO.

If you don't get blinking lights, your problem is mechanical, and statistically, most likely to be a bad splined disconnect on the passenger side of the oil pan.

http://www.offroadtb.com/articles/tech-docs/front-axle-4wd-disconnect

I assume you've already checked the differential oil level on the driver's side?
When I switch to 4WD the lights flash a couple times then go steady... is that indicative of a problem?
 

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2004 gmc
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26,181 Posts
It's normal to blink a few times while the actuator and encoder motor are in transition, then it stays steady on your desired mode. Confirm in your Owners Manual.
 

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2004 chevy trailblazer_ls_ext
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43 Posts
Welcome! This system is my specialty. There are two motors that work to engage 4WD. A front axle actuator that engages a splined collar on the passenger side CV shaft, and an encoder motor that moves clutches and gears in the transfer case. Each of them has a distinctive sound that can help diagnose failures.

But not yours. That trick only works if you get the Service 4WD light on, because the TCCM (transfer case control module) is looking at feedback signals on each of those motors to confirm that they moved to where the controller commanded them.

Your failure is much more likely to be mechanical. The cheaper of the two is the front axle splined collar that the actuator presses on. To confirm this, jack up the front of the vehicle, both sides on jack stands, put it in 4HI and listen to the motors whine. Confirm it's in 4HI and the light on the mode selector switch goes steady. Then turn the driver's front wheel. If the opposite one turns backwards, then the actuator is working and the problem is in the transfer case. If you can spin the passenger side front wheel freely, then the problem is in the actuator.

Some folks have done this work themselves - some pay mechanics. Let us know what the experiment tells you and we can advise further.
A4wd works but 4hi and lo do not.
I as y stated. Both wheels turn in opposite directions when you spin them in 4hi so it is engaging.
Both actuators make noise, the transfer case one is only a few years old.

Now this only seens to happen in the winter time when its real cold.
The selctor switch lights up as it should, tho on occasion the lights will blink then go out. If i put it in nuetral while stopped the bliniking light will go solid as if it is working correctly.

I was told the actuator on the pass side could be freezing up but idk how true that is.

Where to go from here?
As stated a4wd works flawless. The hi and lo during very cold moths doesn't.

04 ext TB 4.2l.
 
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