Some background...

Transmission has been making a bad bearing noise for over a year. I originally thought it was the ISB because I was told the by the previous owner, the Throwout bearing and Pilot bearing were only a couple years old. So while I had the transmission out, I took it to a guy who suggested that the ISB was fine because there was no play with the Input Shaft itself. So I took his word and just reinstalled new OEM bearings, Exedy clutch and lightened flywheel. The TB and PB were a little scratchy sounding anyway, so I thought my problem would be fixed.
Well I start the car and the noise is of course still there and I've driven with it like this for a year and several autocross events with no change in noise.

Now to today...

Pulled the motor because I'm about to install a turbo kit and do a bunch of maintenance. Figured this would be a good time to check out the transmission again. Everything seems to be in great shape, although there was a decent amount of oil in there despite a new Rear Main being installed the year before as well. (Any other suggestions on oil leaks that make it into the tranny housing?)
My main question here is what is an acceptable amount of play in the Input Shaft? There is no side to side or in and out play, but when twisting the shaft in gear, it sounds a bit clunky. I've taken a video of it for ya'll to check out. Can anyone let me know if this indicates a bad ISB??

Tranny is in neutral for the first ~25 seconds, and then put into gear for the remainder of the video.
Thank you!!

 

The sound is the giveaway to a failed ISB. When the car was running but parked, you should hear the rattle with the clutch disengaged, it should stop when you push the clutch in. Was that what it was doing?

If the tranny is out, it's not a LOT more work to replace the ISB and seal. Check out the B/K tranny teardown writeup in the transmission forum. It guided me nicely through my first one.

 

Throwout and pilot are both in good shape still, and the noise was there a year ago even with everything completely cleaned and installed correctly. I did all the work so no questions about whether or not mechanic messed something up. Only thing I didn't do before was determine whether or not ISB was bad, I took it to a guy who had done them before for his advice on that.

But yeah, noise goes away when the clutch pedal is pushed to the floor, typically ISB symptoms. I just wanted to confirm if it was for sure the ISB or if there is some other bearing inside the transmission that I'm not aware of. While it's apart, I think I'll have everything checked out and just replace it while I'm there.

 

There is a lot of bearings on the shafts in the tranny. Even if the ISB is good, the others might not be. Until you crack the case open and inspect, you won't know which is bad.

The ISB seal could be bad allowing transaxle oil into the bell housing. You can't replace it without cracking open the transmission case.

 

Just an update, ISB was bad and I believe the counter shaft bearing was bad too, I don't remember which one it was off the top of my head.

 

If I had to open it up I'm rebuilding it...