So I noticed a while ago that when I put my truck in 4x4 the front end has a strange sound, it does not sound like grinding but not quite like a whine, imagine something in the middle and that what I got going on. I usually through my truck into four wheel drive every so often, usually when I find a mud hole I wanna hit a few times.

Now when I have it 4x4 it feels like the front has a different ratio than the back. I have looked all over the front end to see if I had a leak but it is all dry. Due to rain I have not been able to actually check the front diff for proper oil level. Although I know the 4x4 is engaged cuz the light comes on and the stearing feel changes like it should and what not.

If I can I will try and get a video of what it sounds like tomorrow if I can. But any insight on this issue would be appreciated.

 

Pinion bearings? U-joints?

 

could the "Snap Ring" in the transfer case cause that?

My problem was somewhat similar, then it got to the point where i was driving, then crash, sounded like it was trying to get in 4x4....sounded like it was the front end, but it was the transfer case.

Swapped my t-case (pretty easy job by the way) and all is good.

When i separated my old t-case, the inside was all chewup, pieces of a gear wre scattered about, the chain was loose as hell, and very crooked.

 

Well I finally got a video up of this sound, It is not perfect but if you turn it up you can hear the sound I am talking about.

Also there is no picture, I had to hide my phone from security.

I replace my u-joints and wheel bearings today, and found that my front diff was low on fluid. I still need to replace my tires and get an alignment but when I turn it sounds like everything is binding up. Also this is on pavement and it seems to get louder as I slow down.

http://www.youtube.com/watch?v=w_DAytG0evE

 

I had a similar noise last year, turned out to be the hub was shot. Not a cheap part.