1994 Isuzu Rodeo transmission

check shifter to see if cogs are lining up right it may be jammed between two gears. otherwise it may be an internal thing like a synchro bad for first or shift fork for reverse and not letting it go all the way in gear.

thank you so much for your quick response but what are cogs? and how do i check them

that is where the shifter goes in to trans see if they look like a square or rectangle in neutral they should they shouldn't be worn either or where the end of shifter is should be square like and rounded.