Cant Figure It Out. Please Help

hi, i was wondering if anyone had any ideas of what was going on with my car. i just swapped a sr into my 240 and everything was running fine. it started up and i was able to drive it for 2 hours or so and then my gears started to grind out of no where. i cant shift into any gears even with the clutch in. i have to turn my car off and then i can shift once and then i cant shift into any other gears. the sr i got came from an at and my car was already a mt. so i had to take the clutch off and do all that other stuff. got the torque specs and tightend everything right. does anyone have any ideas?? thanks

shit my bad, i guess i should have put this in the technical...

hmm, sounds like a problem with your master cylinder/slave. you may need a new slave, i had to use a new one when i converted my silvia to manual (the used one i had was busted or worn out)