Redline MT90 transmission oil works wonders for transmission with synchros. It stops grinds and what not. You should try it.
my celica sometimes grinds in reverse (unless i seriously mash the clutch down with lots of force). would this also help?
all you need to do is if the car is put the car in neutral, let the clutch out, clutch in, shift into reverse.
if you start the car, leave the clutch in the entire time, and go into reverse, it grinds sometimes