Diagnosing 4wd Confusion...thought it was solved...its not:(

[Trail X]

TBs didn't have an AWD option.

[Mudwheelin]

Thats what I thought as well. I was confused when he was talking about it. I think im going to play it safe and buy a new one. Ill buy the one from the wreckers if someone is interested in it and wants to buy it. Thank you James and Bill for the much needed help and advice. This site has saved me thousands!

[Mudwheelin]

Ok I just ordered it. Came to $355 CND. This has been an expensive month so far...

[fishsticks]

Roadie... or anyone else...I found one at a wrecker for $125. Its out of an 06 trailblazer LT. The guy didnt know if it was an Awd one or for the one I have. Or does it even matter?

I'd run it even if it was an AWD one. Stronger, less parts to fail. Just pull the actuator out of the old one and tie it up and out of the way.

[Mudwheelin]

Well thanks for chimin in after I just paid for the new one. Lol. I never thought about that. Ill probably buy the one from the wreckers just to have a spare handy.

[Trail X]

You can always sell it here if you don't want it.

[Mudwheelin]

Id buy it tomorrow if I knew someone on here wanted it.

[Mudwheelin]

Ok so I though it was fixed. But it kinda is and isnt. I got stuck in some snow deep snow today. Went to put it in 4hi and it made a weird clicking noise that sounded like it was coming from the drivers side area. My fluids were just changed so its not that. I just replaced the 4wd dissconect. The noise is only there when its in 4hi. Its sounds like its trying to grab but wont.... Im really starting to get anoyed with the TB. Its starting to seem like every week its something else. Any help on this clicking noise would be great.

[Mudwheelin]

Please read what I wrote above....I thought it would bump it if I edited it. Guess not.

[Trail X]

Please run through the "Diagnosing the 4WD System" article again, and follow those steps to a Tee. Report back here and clearly and very concisely spell out what you do, and the result.

Maybe even take a video... reading through your previous posts makes what you did very unclear (for example, do not use the word 'it' in your description, spell everything out).

[Mudwheelin]

Ok, so I went through all the 4x4 tests. Every method I tried says that my 4wheel drive seems to be fine. I was just out testing the TB a few minutes ago. At first I put it in 4hi and there was no power going to the front tires. I then put it in auto, and still nothing...I put it back in 4hi and all of a sudden it was working. I tried a few hills just to be sure. I put it in auto and that worked to. I was just pulling into the garage and figured Id make sure it was working. So I put it in 4hi, and again no power to the front tires. Then the 4x4 switch lights went out and a service 4x4 light came on underneath the change oil light. I havent seen it there before, its usually on the top left of the cluster. I turned the truck off and turned it back on and 4x4 worked great again. Im not hearing any clicking noises anymore. It seems like the TB has a mind of its own. It works when it feels like it....is this looking like its something electrical? I love this suv and Im far from giving up on her! And I really like this forum:)

[Trail X]

Intermittent problems are always hard to diagnose, so it may take some time to narrow it down.

When the service 4x4 light comes on, that means that the TCCM identified a problem. So at the root, it's something that can be identified electrically.

Next time that you KNOW 4x4 is not working, stop right there and run through the diagnostic routine. This will help identify where the problem could be.

My gut says it's possibly the front actuator plunger assembly (the black box that mounts on the disconnect housing), but I'm not sure I can say that 100%, given your explanation so far.

[Mudwheelin]

I wish I could just stop anywhere, but I have 3 feet of snow on the ground, so stoping to jack the front end up isnt really an option lol. I would hate to bring it to the stealership...but its almost looking like thats my only option. I have a 14 month old daughter and a wife, so keeping them safe is most important. I wish this 4x4 issue was an easy fix, but they never are.

[The Roadie]

Besides the clicking noise, are you hearing the two motor noises for the front axle actuator and the encoder motor at the proper times?

[Mudwheelin]

Yes I hear both motors when I select 4hi or low and auto.

[Mudwheelin]

Might be a stupid question...Am I supossed to reset the battery after fixing this? Could the computer be messed up thinking that the 4wd still has a problem? I didnt see a dissconnect battery in the how to...

[The Roadie]

Never need to disconnect the battery. The TCCM resets at ignition on, but a fuse pull for the TCCM alone might do something. I'm with JD. If you hear the motor noise from the front axle actuator, and its movement isn't being read back by the TCCM and you get the Service 4WD light, then the problem could be either electrical or mechanical in that area. But if you're not able to work on it comfortably, you need a heated garage or a mechanic with a lift to look at it. If not a dealer, make sure they know how our platform's systems work.

[Trail X]

Might be a stupid question...Am I supossed to reset the battery after fixing this? Could the computer be messed up thinking that the 4wd still has a problem? I didnt see a dissconnect battery in the how to...

Is the service 4WD light coming on immediately after starting the vehicle? If so, that could narrow it down some.

Like Bill said, the system resets the diagnostic light when the vehicle restarts.

You may be a good candidate for an AWD splined disconnect sleeve.

[Mudwheelin]

The service light comes on only sometimes when I start it up. It also comes on when I try to put it in 4hi.

[The Roadie]

Yes I hear both motors when I select 4hi or low and auto.

You should only hear BOTH motors in a mode transition from 2HI->A4WD and vice versa. If you're jumping two transitions, such as 2HI all the way to 4HI, you could be confusing the issue a bit. From A4WD->4HI, ONLY the transfer case encoder motor should sound off.