when im reversing in my gsr. the gearbox makes a horrible noise, sounds like a grinding noise. tell me someone

 

All manual transmission cars w/ non-synchronized reverse gears make a "whirrrr whirrrr whirrrrrr" sound when you back up.... probably not the best way to type out a description of the sound

 

lol..hey..you do whatcha gotta do..made sense to me!

 

check the oil level.....
may be oil too old

 

Most tegs go into reverse hard too in order to prevent going from 5th directly to reverse and f-ing up your car. All of the teg ive driven do this. Maybe you didnt have it in all the way. I know ive ground mine once or twice being absent minded about it.

 

mine does the same thing if you put it into reverse if your rolling at all...sounds fine when your at a full stop. kinda sounds like a crunching noise riight?

 

it clashes when first going into reverse (not engaging clutch, but actually pushing the selector into gear) because you're moving spur cut gear into spur cut gear. all other gears are sliding syncronizer ring accross clutching teeth that are speed matched by a blocking ring.

if you are rolling in gear in reverse w/ the clutch engaged and you are hearing grinding noises, some of the teeth on the idler and other reverse gears (can't think of it off the top of my head, i'm caffein buzzin like crazy right now) have chipped teeth.