Clunk Clunk Sound.

[Martin]

The link in question.

Living with a Clunking Drivetrain? You Don't Have To! - MustangForums.com

2005-2014 Mustangs - Living with a Clunking Drivetrain? You Don't Have To! - I had the clunking drivetrain for a while. I'm talking about the occasional clunk sound I would hear when at a stop, either shifting from park to drive or reverse. I was told it was normal, every S197 does it , It's...

mustangforums.com

Just came across this on another site while looking for something else:
"I had the clunking drivetrain for a while. I'm talking about the occasional "clunk" sound I would hear when at a stop, either shifting from park to drive or reverse.

I was told it was normal, "every S197 does it", "It's from the two-piece driveshaft, that's how they all are".

Well, I can tell you the fix is rather easy, and you don't have to live with it. Turns out my clunk was from the slip joint on the driveshaft being dry. After lubing it, it's a smooth as silk, not a single clunk since then.

If you have the clunk, have your slip-joint inspected to make sure it's lubed correctly."