2000 Chevy Tahoe Z71 4x4 Not Engaging

[snowchaser]

Hello and thanks in advance for the help.


I have a 2000 Tahoe Z71 Special Edition (think 90's body style) that is not engaging the 4x4. Was working great and took it out one weekend and will not engage.


I have replaced the actuator on the front axle, the new one actually makes an audible noise, but apparently was not the issue. I then replaced the selector switch as my lights would only function when they felt like it and the switch needed replacing anyway. Now the indicator lights work, but still no 4x4.


-When I press Auto 4x4 you hear the axle actuator engage and the light stays on for Auto 4x4. I don't know if that actually works because I never use that feature and I really don't need it.


-When I press 4HI you hear the actuator engage and the button lights up (or maybe blinks), but then the actuator can be heard disengaging and the light goes off and it stays in 2HI.


-When I press 4LO (in neutral with engine running), that indicator flashes for a bit and the actuator can be heard, then the 4HI light lights up. I haven't tested to see if 4HI is actually engaged at this point, because I suspect it is not and I really need 4LO more than anything.

This should be the same as the 96-99 pickups so that is why I am posting here, it's a weird problem so I'm hoping someone has come across this issue. Trying to avoid replacing the transfer case actuator/motor as it is pretty expensive and I'm not sure it is the issue. Is there a way to test it or am I looking in the wrong place?

 

[Fless]

How's the fluid level in the transfer case? Any leaks, cracks, etc.?

I'd recommend using a good bidirectional scanner (like a Tech 2) on it so you can see what's going on. The lights on the switch will be of limited value, since they are controlled by the encoder (transfer case) motor and the transfer case control module. With the Tech 2 you can see any codes or conflicts in the TC data.

I'll take a wild a$$ guess and say it's the encoder motor, but there are good ways to confirm that before you spend the money. My 04's switch lights were indicating it was in 4HI but it was in AUTO, which I suspected due to how it acted.

 

[snowchaser]

Thank you. I'll see about the scan. Is that more than an Autozone OBDII scan? If I pull the encoder motor and leave plugged in, shouldn't I be able to see it move (or not)?

 

[snowchaser]

I think 4HI actually is engaging when pressing 4LO. If that helps. Tested on a hill. Also, planning to do the fluid change prior to removing encoder motor.... No leaks or cracks.

 

[Fless]

Thank you. I'll see about the scan. Is that more than an Autozone OBDII scan? If I pull the encoder motor and leave plugged in, shouldn't I be able to see it move (or not)?

I would think a more advanced scanner would be needed to see the transfer case codes and operation.

The encoder motor instructions, at least for mine, specifically state NOT to operate the motor while it's physically disconnected from the TC. I'm not sure about yours, but it may not end up in the right position if you do that.

In what part of the country are you? If the AZ scanner doesn't work for the TC, perhaps someone nearby with a Tech 2 or similar would be able to help out.

 

[snowchaser]

I would think a more advanced scanner would be needed to see the transfer case codes and operation.

The encoder motor instructions, at least for mine, specifically state NOT to operate the motor while it's physically disconnected from the TC. I'm not sure about yours, but it may not end up in the right position if you do that.

In what part of the country are you? If the AZ scanner doesn't work for the TC, perhaps someone nearby with a Tech 2 or similar would be able to help out.

NM but no need, it was the stepper motor. Thanks for the info. Yep, both old and new had a warning not to operate un-attached.

 

[exp500]

Please Edit your 1'st post. (SOLVED) Thanks