during casual shifting from 1-2 i get this brief grind just as i slide it out of first gear, before i even pass neutral to get into 2nd. it used to slide into 2nd smoothly with no problem at all. this is after the tranny has been well warmed up. could this be a worn syncro? i have missed a few 1-2 spirited shifts but no mis-shifts at all.. would changing tranny fluids help? thanks in advance.

 

Never heard of that before, grinding going into neutral. Try swapping fluids with some GM SynchroMesh and check back.