boostin99em1

so lately my car has randomly been popping out of fifth and is really hard to get in second but sometimes will go in no troubles. replaced shifter bc it was bent didnt do anything and checked shift linkage fork and didnt notice anything wrong with it.anyone have any ideas?and also at a high rpm it wont go in 3rd. sometimes grinds most of the time it just wont go in without a sound. and no im not missing 3rd i could take all day to put it in 3rd and feels like it just wont let it go into gear at all.figure if it was syncros it would grind all the time?