1999 Silverado 4wd

Having some issues with the 4wd on my 1999 Silverado 1500. The auto 4wd seems to work great, but 4Lo and 4Hi don't seem to work at all. The switch seems to work fine, as when i hit the buttons, the light flashes for a few seconds then comes on like it's supposed to.
Also, when i hit 4Lo, i can feel it lock in down below. However, nothing seems to happen with the front tires when i go to pull something. Any ideas on what could be wrong? I've read that it could be the ABS/traction control system that's messing it up somehow...

I had the same thing with my 2001 Siverado 1500. It turned out to be the 4wd gear box. It was about $1500. I was not a happy camper. I hope that isn't the problem that you're facing, but it sounds the same.

Thanks Rich - Also, i took it to my garage and they checked it out on the hoist, and said that everything seems to be working correctly. They said it shifted in and out of 4WD good, and the front end turned when it was locked in. Seems weird, but i'm 99% sure that nothing is happening with the front end when the tires are on the ground... I can be stuck, put it in 4HI and nothing happens, put it in Auto4WD and crawl right out....

Do a search for chevy 4 wheel drive actuator

Sometimes the splines won't engage because they aren't lined up correctly. If your really stuck and you THEN put it in 4wd, you might still be stuck unless you can rock the truck enough to engage the splines. It's happened to me a few times on different trucks I've owned and they have all been 4wd. All GM also execpt one Ford, "never again".

I have a 99 that is doing the same exact thing, I was just wondering if you figured anything out on your truck? Hopefully you can give me some insite before I start throwing parts at it. I have already replaced the front axle actuator but have not messed with the trasfercase yet.