problem

[HMNGSupraMKIII]

i went to turn my car on after 4 days of lettin it sit in the garage. its a 5spd all stock. and i pressed down on the break it seemed to go down alot easier than normal. so i just turned the car on and it went on. but when i try to put it in reverse it started to grind gears. i try to put it in first but couldnt go. is this problem due to i need a new clutch of is it the transmission itself?

 

[SupraTurbo_MK3]

Sounds like a clutch so far from the info you have provided......Mine grinds everytime I go into reverse and sometimes it doesn't want to go in but I just put in first then reverse and it go is in fine but I think my problem could be the shift fork because I have a new 3000lb 6 puck clutch