Awful deceleration noise [Videos inside] - help!

[butteski]

Happens in any gear when I take my foot off of the gas. Does not happen in neutral or with my foot on the clutch pedal. The problem sounds like it's coming from the trans (drivers side, front of car). I've had this car for a little over a year and it's always done this, so I've avoided decelerating in gear. I just had the trans rebuilt and the problem appeared to be resolved... for about 50 miles. Then the noise came back. It's been back for about 200 miles now. Before and after the rebuild I've used 2 different ACT HD street clutches (new one installed after trans rebuild). I understand with after market clutches there's always a likelyhood that new noises will be introduced but this sounds like a grinding/drilling noise that I can't imagine is coming from the clutch assembly. I took some videos to illustrate how awful the noise is (the noise is louder than it appears in the videos). Has anyone had a problem like this? Any ideas at all?

Third gear: http://www.youtube.com/watch?v=xeSBganMKFA
Third gear, windows rolled up: http://www.youtube.com/watch?v=lrjd3-RWjIQ
Fifth gear, higher pitch noise: http://www.youtube.com/watch?v=jAesYMTH9Eg

[drifthobo]

My friend had this sound on his X upon deceleration. It was his transfer case. I really recommend you change your Transfer case fluids ASAP and see what it looks like and put some fresh fluids in. Then do another Transfer case fluid change 5k miles later to check up on it again.

[evobros]

Yup sounds like a transfer issue.

[butteski]

I just recently replaced the transfer fluid with the OEM gear oil. I've drained and refilled with new OEM gear oil in the past as well, and that never had any effect on the sound.

Drifthobo, do you remember what specifically was wrong with your buddy's transfer case? Looking through the access panel, the teeth for both the ring and pinion look perfect. No visible wear or chips. Was it a differential bearing inside of the transfer case or something...?

And thanks for looking, guys