I have a 96 Tahoe, for some time now when you turn the steering wheel it would make a quick squeeking noise. I have been running oversize tires on it for a couple of months with no problems. Now when you turn the steering wheel hard to the left or right it acts like it has four flat tires and doesn't want to go? It drives and turns slight turns, its just when you try to turn hard or make a sharp turn like pulling into a parking spot?

 

Not sure about the squeaking issue, but...
By chance is your ride a 4WD, and, do you have it in 4WD Auto or Hi ?

 

seized/tight ball joints. When they dry out or the boots tear and water get in them they don't rotate smoothly.

 

Do the 96's have the variable speed sensitive steering? if so it could be the sensor the the power steering assist going out....

 

I took the dash off recently to install a new stereo so maybe I hit the 4 wheel drive button or something? It does sound maybe to me like the ball joints...not sure but I will check all of these things. Thanks for the help!