Just wanted to mention something cause I care about my Mustang bruthas-
*Adding trans tune to fluid and driving with it in the trans, worries me a tiny bit. It's most likely just fine. Just a FYI- for auto's and manual tranny's, using synthetic has been a staple of mine. If you do use synthetics, they have very strong detergents inside and maybe provide the same effects as trans tune, but much safer, or conventional like.
**Also, I use synthetics in my differential (Amsoil & FRPP friction modfr), tranny (Mobil1ATF), power steering sump (Mobil1 ATF), Engine (Mobil1 ES). Also use Militec1 additive. Motorcraft oil filters.(used to use Mobil1 or K&N oil filters).
If u think of it, update me sometime down the road on how it worked. -I do remember you saying that it was hesitating or something similar too which may of been main reason.
Just want to be helpful, no disrespect Brudda!!
'97 3.8L V6
1996 SVT Cobra White