I took mine to ford for that same noise and they replaced a shock and the noise is still there. Would like to get it fixed since it annoys me.

 

Has anyone been 100% successful with this rear squeak? I have a 2013 GT Conv and the squeak happens at slow speeds just going over slightly small bumps.

I'll check out the trunk, lights, etc. Just hope it's not a suspension issue...

 

Could it be rear sway bar bushings? Just a guess.

 

Blaster white lithium grease! Spray it on lower control arm bushings and sway bar bushings. Presto...abra cadabra! No more squeaks and creaks! It works! That creak was driving me insane but it's all in the past now. Joy!

 

It sounds like a bushing creak. Like others have said lube the sway bar end link bushings as well as the upper and lower control arms bushings.