Hey all. I have a K24 swapped S2K I've been driving without major issues for about 7k miles till now. All fluids including trans and differential were replaced while building the car.

Seemingly out of nowhere while driving home from work I got a nasty clunking sound coming from what I thought was the differential at first.

After getting home I put the car on Jack stands, I
put it in gear and found the sound seemed to be actually coming from the transmission. The car has 99k miles on it and the vin on the transmission matches the cars, so I know it's the original transmission. The fluid looked okay to me in both the trans and differential (which I checked just in case).

Here's a couple videos of the noise. It occurs any time the driveshaft is moving including in neutral and doesn't matter if I have the clutch in or not. I can definitely feel the problem from inside the car it feels terrible and seems worse at lower speeds (under 40 MPH or so).

Under the car:
https://youtube.com/shorts/7PhWS4TSVTA?si=BGjrz8dCFd47AYqt

Inside the car:

https://youtube.com/shorts/qzVYqtrMwnY?si=KaFfzfmzbinlPG9-

If I move the driveshaft in neutral with my hand I can actually feel something binding on it about once a turn.

Every gear works fine and shifts smoothly. Strange issue to me. I'm suspicious of the trans output shaft bearing but it sounds so much worse than any bearing failure I've ever heard. Any assistance is greatly appreciated

 

Is the fork fully seated?