4speed to 5 speed linkage, HOW?

so i have a 5 speed box in my caddy and i am finding all 5 gears when i drive fine, Most of the time!!
every once in a while it sticks going into 5th and pops my gear lickage arm off.

i was told that if i extend the flat verticle bar about an inch it would stop this, is that correct?

Did you change the linkage arms from the 4 speed to 5 speed linkage arms I think they are slightly different....