4x4 inop

[iainkirkham]

i have a 2004 trailblazer ext. i was driving on some fairly mellow trails about two or three months ago when my service 4wheel drive light came on and now none of my four wheel drive gears work. when i switch the selector switch it still makes a noise like it is going into a4wd or 4hi but it never engages and the light for the gear i am trying to select flashes while the 2hi light stays on. i tested it on the hardball to see if it was going into 4hi or 4lo and there was no skipping of the front tires. any ideas guys? cmon i know THE ROADIE can help me. you are the trailvoy expert.

[the roadie]

Welcome. Pretty gutsy for a first post to summon me like that. :dielaugh: :rotfl:

http://www.roadie.org/bat-signal.jpg

Anyway, you could have lost your front axle actuator. If you've read my posts for a while, you'll notice I advised to go out and with the engine off, with the shifter in neutral, and the ignition on, to just listen to the two different noises the actuator and the encoder motor make.

This is why. Now you need to compare that good set of sounds with what you have today.

So do you get a high pitched whine for 2 seconds during a 2HI->A4WD mode transition and vice versa? Combined with a low pitched 1/2 second noise from the encoder motor? And the low pitched noise happens on ANY mode transition, not just into or out of 2HI?

Have you looked at the connector at the front axle actuator to see if it's pulled out?

How about fuse #48 under the hood?

When you put the transfer case in NEUTRAL according to the owner's manual directions, does the "N" lamp light up?

[iainkirkham]

alright so i know now that i need a new encoder motor. i am stupid and decided to pull it out to see if the gears were stripped and when i put it back in the switch lights no longer light up and there are no noises what so ever. so i think i broke that. as for the actuator where is this located? i had some wires hanging down along the front axle that plugged into this plastic module on the passenger side of the oil pan i pulled that off but i have no idea what it is. i am totally trying to avoid the expensive dealership costs of fixing things. i am going to my local junk yard on monday to pick up another encoder motor. and maybe the computer for the 4 wheel system. thanks roadie i know you always got the answers.

[the roadie]

thanks roadie i know you always got the answers.For now, I'm am filled with questions, not answers. And you hardly answered any of the ones I posted.

WHY would you disconnect wires from an item you don't know the function of?

Is this it:
http://forums.trailvoy.com/showthread.php?t=46356

Most of the answers you need are in many historical threads. Run a search for "front axle actuator" and read for a couple of hours. If you don't want to pay a dealer, you need to educate yourself here. If you come across a term you don't understand - SEARCH for it, just don't stumble blindly on like a bull in a china shop.

Or continue to guess and break stuff you have no idea how it works or why it's broken.

At this point you might have just one blown fuse, but I haven't heard yet that you have been checking fuses.

[iainkirkham]

so i checked both fuses number 8 and 48 they are both good. i listened to the sounds and for as far as i can tell only the encoder motor is doing anything. i pulled off the front axle actuator and inspected the gears inside and they are all fine. but just to try something i went to my local junkyard a bought an actuator. after installing it still nothing. i then noticed that when i put the t-case into neutral the "N" does not light up.