First Gear pops out?

[FunWheelDrive]

After putting a 3inch exhaust put on my car, i've been driving about 100miles and on this last drive at the end of the drive i'll go to put it in first by going second to first, and it "seems" like it's going in, then you let the clutch out, and you hear a POP as soon as the clutch grabs and the car goes into neutrul.

If i put it really slowely into second to first really slow or really aggressily then it'll go in sometimes, it's half and half, though the last 5 times i tried it went into first and stuck. The tranny shifts completely the same as it did before, no grinds nothing, i check my clutch fluid level and it's just above the min line by like 1-2mm. I'm going to try and bleed my clutch tommorow, also important to note, when the car is in first and it's moving only once has it came out under light accel, never under heavy, and it will pop out 70% of the time under decell. I don't think it's my tranny syncro's because it's so inconsistant. Also my master cylinder looks to be leaking aswell.

So, did my tranny on my 7m-GTE decide it doesn't want to be a tranny anymore or is it just the clutch no disenging all the way? Please help.