T5od poor shifting
 

Hello all I am having an issue with my 06 Mustang coupe with a t5od transmission first to second gear change extremely knotchy some times almost impossible in the down shift when warm . I have changed the clutch master cylinder and am confident it is bleed adequately
I have also changed the transmission fluid with an off brand dextron three atf.
I have since heard Amsoil signature synthetic atf Is the cure anyone have the same experience
thanks In advance
Kip