four wheel not working

[longracing25]

I have a 2001 Tahoe 4x4,..when i put it in nuetrel and push into 4-hi or 4-low,..i hear a clank sound like it's engaging up front,...but it doesnt seem to be working. The back tires spin, but not the front,...and it slides around like a 2-wheel drive. The 4x4 fuse is okay. The lights switch to whatever i select okay. the wirie connction is connected on the front axle. I would think if the transfer case was bad... i wouldnt hear the sound up front. I have a had my "ABS" light and my "brake" light on for nearly a year now. I took it to the dealer probably 5 times...and they couldnt fix a damn thing. They said they did, drove away,...and nope, there's the light. Could this have some electrical impact on my front end not working? The lights came on after those idiots changed the right front hub. Which is why i took it back,...it was always free,...cause i blamed them.

 

[longracing25]

someone said you need to put it in 4x4 and backup a little like the older chevys, is that true?

 

[Donut Slayer]

Nope. Most likely the actuator on the front diff is broke. And the ABS and brake light is probably a wheel speed sensor that has gone bad. That's a common problem. They are located in the front hubs on both front wheels, and on the transfer case for the rear. I'd fix the speed sensors first and see if that fixes the 4x4 problem.