1st 2nd grind issue is well documented in the GT 5.0 threads as well.
I read quite a few posts on this.... I also get the 1st 2nd grind on my 6M gt, started doing it pretty much from the get go... problem seems to disappear as the car warms up, I have always allowed the car to run for at least 5/10 minutes in colder weather,but starting off to my office, it would ALWAYS grind going into 2nd gear.
Not a fun feeling with a brand new car grinding with less than 300km.
In my opinion, FORD should have addressed this issue BEFORE they started selling it,lots of disatisfied and upset owners over this,and the fact FORD has issued no official comment in this regard,NOR produced a TSB for it.
Im surprised that it's also happening on the GT500 Shelby, and you guys have a different transmission BUT having the same problem as the GT 5.0 MT6S.
Im patiently waiting for FORD to address this issue,the sooner the better.
2011 GTCS Candy Red;Premium leather interior package, Remote start, security package, upgraded speakers, 6MT 3:55. 35% tint all around, Borla "S" axle backs, & clear corners.
The rest is all FORD