I have a 2003 f150 KR when the truck is warmed up and i am making a slow turn in a parking lot if feels like the 4x4 is trying to engage. I had all the fluids changed out to redline fluids. But that did not help. only does it when the truck is warm makes a noise also like its fighting. Not sure what it is. Is it the transfer case

 

Do you have a traction lok rear? If so, the clutches may be trying to lock up. Common problem usually cured by changing out the lube and adding the proper viscosity modifier.

 

The problem sounds like its coming from the front Diff. not the rear. I did add the right fluids but still no good.

 

I think it is the rear sounds like the clutch is trying to lock up when i make a slow turn. in parking lots. Changed the fluid out to Redline fluid but it still does it

 

Did you add the Ford friction modifier?

 

No it says it has it in

 

Put it in anyway.

 

1 bottle of friction modifier do I buy it from ford or any parts store

 

Buy it from Ford unless parts stores have the Motorcraft XL-3 additive.