Just purchased a 14 F type with 5.0 and read alot on the coupler issue and wondering how much free play on the pulley is acceptable if any? I was getting a clunking on shut down, although the cold start sounds fine. I read the TSB and took my belt off and have about a 1/4" of free play before the pulley engages the rotors. Bearings feel fine. I noticed the supercharger has been off before since I have the updated coolant pipes. 80,000 miles on the car.

 

All in what you can tolerate. If it was making noise at 80,000 with mine I would replace with upgrade part.