A/C compressor howling when on
 

I have a 2011 F150 FX4 with a 5.0 the A/c compressor makes a howling noise when on and goes away when it is turned off. can i replace the clutch only or do i have to replace the compressor?

It is very likely you can just replace the clutch. Certainly try that first as the cost difference of the two alternatives you mention is HUGE.

Replacing an A/C clutch is fairly straight forward.

When you put the new clutch on, adjust it so it is about a business card thickness away.