Good look OP! Sorry for the troubles.I’m posting because I see a few people on the site right now... and I’m HOPING someone can answer/assist. Same issue with my 2017 Shelby again and I really don’t believe Ford. I’ve had to take it there twice for the same problem and both times they came up with different solutions. It’s hard to explain it on hear without the video but around May (and it’s NOT cold in San Antonio, Texas) I would hear this noise like there was something stuck in the cooling fan when I would start it. It’s not a tick tick tick, it’s not a rattling sound it’s not a rapping sound. Sometimes it happens and sometimes it doesn’t. The second time it was at the dealership is when the TSB 46173. Now here is my question to you guys...if you take a random regular car to the shop because there is a sound coming from the engine aren’t the mechanics able to diagnose piston slap as the problem???? I don’t understand why they couldn’t diagnose a problem within the ten days they had my car but this magical piece of paper saved the day. I would LOVE to post the video of my Diesel engine but it didn’t work.. Does ANYONE have an answer???