2000 CHEVY BLAZER LS 4X4

I just replaced the passenger side wheel hub assembly 2 days ago because I could hear grinding and was told by my mechanic that it was going bad. Before replacing the hub I could hear a whirring noise coming from the passenger side and upon breaking i could hear a clicking noise until I stopped then I would hear a "CLICK" as if something was engaging.

FAST FORWARD - After replacing the dead hub all seemed well until yesterday as I reached 45 mph the whirring came back and as I decelerate the clicking and final click are back.
Any idea what this could be would be so helpful.

I tried the reverse with the steering wheel all the way in both directions and no noise or anything has happened. My last thought is possibly a defective Wheel hub assembly since I just installed new ones on both sides about 2 weeks apart and the noise is still coming from the passenger side.

EDIT
I forgot to mention that when in 4wd there is no noise or clicking as i decelerate if that helps at all.

EDIT
Ive tracked down the problem a little further, If i engage 4wd the noise goes away which is leading me to believe that my 4wd is not fully disengaging anyone have any insight on this or where to look for a fix?

 

3 or 4-button switch in the dash?

3-button = NV233 transfer case which has a mechanical switch on the transfer case that can fail to close off and vent the actuator completely when in 2HI.

4-button = NV236 transfer case which has an electronic solenoid that could possibly be sticking slightly open, allowing engine vacuum to pull on the actuator when in 2HI.

This would result in there being vacuum pressure to the actuator with the engine running and the truck in 2HI. This can be tested by disconnecting the vacuum line at the actuator (located under the battery).

Another source of this problem could be a sticky actuator cable or a broken return spring inside the front axle itself.

All of these topics and more are discussed throughout the forum. 4wd threads are quite prevalent. The Tech Article (DIY) section is quite informative and with the indexes that are in place, it should be quite easy to find what you are looking for.

Hope this helps.

 

Thanks for the response and sorry for the double post, I've searched quite extensively but have not been able to find anyone with the same symptoms. I have the 3- button 4x4 so I assume i should disconnect the vacuum line under the battery? once I do this what should the result be? thanks again for your patience and response.
-J

 

Rather than write out the same thing over and over again, I consolidated all of the information into a tech article:
4wd Front Axle Clicking When in 2HI - Goes Away when in 4HI/4LO