I have a 2002 F150 FX4 4x4 XLT Ext cab. When I turn corners my differential doesn't allow my truck to turn w/o spinning tires. I was wondering if this is normal or is there a cure?

 

Slow Down then. It sounds like you are going around and accelerating hard out of the corner and spinning the inside tire. This will be more problematic if you do not have a limited Slip.
That, or you need new tires

Brian