Rancidracer86

Ok, i own a 99' Honda Civic that used to have a D16 in it. We recently upgraded the engine and transmission to the B16a. The motor runs great but the Transmission does not. It started with just slipping out of 5th gear when cruising down the road. It had fluid in it. Well now it won't come out of whatever gear it is in even though the gear shift moves into all gears the actual transmission doesn't. I let off the clutch and it stalls weather you use the gas or not. I need some help diagnosing the problem before i just start buying alot of random parts that it could be.