[Floyd]

Popping out of second gear is the classic textbook case of "its worn out". Mac VP is always correct and you should read his post carefully. There is no single item or adjustment or quick fix to solve the actual problem. You need to rebuild the whole thing because the primary cause is the clearances in the cluster gear and most importantly, in the second gear spacer. You cannot get to these items without taking the entire thing apart.
Just my opinion.