So, on a beautiful New England day yesterday, I took my 2013 GT500 for a nice cruise. I hopped on the highway and and while cruising at 70-75 mph I hit the gas pretty hard, the tach rolled up and you can hear the ususal blower whine, but the car didnt hook up like usual, just spun. I did it again, same thing. Almost like wheel spin ( I'm at 717 rwhp) but at 70 mph? Car doesn't have any issue hooking up at slower speeds running through the gears other then the ususal tire spin, but on the highway, different story. I do have a smaller pulley and a Metco aux idler on it to take up any slack. Is it loose, tire spin at 70, new clutch time ?? Never had this issue before. Any advice would be helpful. TY