This pulley looks like it is coming apart. This is on a 08 V6 mustang. The drive belt was recently changed but recently, I cut the car on and smelled the rubber burning and squealing. Has anyone ever had to change one? Need instructions.

 

Quite common to have that go out like that. There should be threads on replacing the crank pulley.

 

Found some, this one should help. Crank pulley or harmonic balancer.

https://mustangforums.com/forum/v6-s...n-4-0l-v6.html

 

Yup - harmonic balancer fail. Poor design by Ford. Follow JimC's link. Takes about an hour at most. Got mine from Napa Auto. Stretch bolt is a dealer only item however.