Will Baty

I am running in 2x4 (no auto) when I pull into a parking spot or make a sharp turn I can feel at slow speeds and hear the front end binding/pushing just like I am in 4x4 but not as harsh. I am confused because when I put the truck in the air (all four wheels) then start the truck put it in drive just the back wheels spin. The front drive shaft is also spinning but there is no power to the front. So why does this thing push when I am turning? I can also hear and feel a slight vibration and growl at 70mph that I have never felt before. The truck also feels like it is working a little more going down the highway. I just checked my gas mileage and it was 14.23 mpg, I normally get between 15.8 - 16.2 around town. So I know something is wrong, ant ideas or have you ever heard of this?

P.S. The 4X4 is working fine in and out of 4 low.

Thanks,
Will

Will Baty

Any thoughts????