I have 2000 mustang gt and it used to grind when you would go from neutral into 1st and same thing for reverse. To get it not to do that you had to put it into 2nd than 1st and 5th than reverse for it not to grind. I recently installed a new clutch cable (fire wall adjuster design) and now I can shift into reverse no problem and first gear did get better sometimes it would shift into first perfectly fine, sometimes it would just shift hard or grind as well. Because the new clutch cable fixed reverse it makes me think maybe the car might just need a clutch (maybe the clutch isn't fully disengaged ), the old clutch cable was loose down at the pedal. Any insight what the issue is: could it very well just be bad synchro's or just a bad bad clutch, hopefully not a trans rebuild.