Squeal on hard acceleration?

[gedaraid]

I have a '13 SHO with just over 15K miles on it and about 2 months ago (1.5K miles ago), I started having acceleration issues at highway speeds. Like hard acceleration from 60-80mph just felt and sounded non-boosted, which I have read and heard all about issues with turbos on the eco-boosts so not really the question. But along with this issue, if I accelerated hard from a stop or roll, the car would take off like it's supposed to, but I'd get a squealing sound that sounded like it was coming from the rear of the car right after the shift. Thought maybe it's an issue with power transfer from front to rear wheels?

Took it to the dealer and of course they couldn't replicate any of it, blah, blah, blah. I took the service mgr out in it to show the acceleration issue and was able to produce the squeal and he said he thought it was tire chirp from the acceleration... uh... thanks for nothing! definitely not tire chirp! (starting to understand why they can't fix anything)

Anyone had this issue? Are the two issues related or just coincidence?

Thanks!

 

[SHOrod]

I had a chirp or squeal after hard shifts in my tuned Mountaineer which was also AWD. I mentioned this to Torrie thinking it might have been an issue with the tune. He very confidently responded that it's the serpentine belt slipping slightly from the firm shifts. As I paid closer attention to it, that totally seems plausible.

-Rod