Help! Cant figure out what this noise is!

[Jmurrz]

Hi everyone, I recently started hearing a noise coming from what I thought was the Differential. It happened immediately after I was testing my WOT Shifting so I have a feeling that is what did it. I noticed a noise that only happens when the car is not under load. When it is in load there are no issues. Even when I push my foot on the clutch to shift (once moving) the noise is there for that split second until I change gears and put load on it again. I felt my brake petal pulsing to this noise as well. When I put it on the lift it sounded like it was coming from the pumpkin, no noise from the trans or anywhere else so I pulled it and dropped it off.

I thought it was gears, a differential, or bearings in the carrier so I dropped it off to my guy Kevin Hand from Wicked to have it freshened up. He took the cover off and said that upon inspection there was no metal and everything seems to look good, without him really tearing into it.

I tried to explore what else could be making this noise so I checked the drive shaft, drive shaft U-joints, half shafts, hubs, and brakes. Everything looked good, there is no play in anything that I can see and with the whole IRS on the ground it would be hard to miss anything obviously broken.

I am just trying to see if anyone has heard this noise before and what it ended up being. I just don't want to waste my money rebuilding a diff with components that only have 20k miles on them if I don't have to. I also don't want to waste Kevin's time because as many of you know, he is a very busy guy (for good reason).

SO without further ado...
[video]http://vid1350.photobucket.com/albums/p777/Jmurrz/Mobile%20Uploads/C3359EB1-68B5-4A50-9176-1684D9CDB169_zpsteotpia4.mp4[/video]

[video]http://vid1350.photobucket.com/albums/p777/Jmurrz/Mobile%20Uploads/4433EF5F-4412-48E8-BC2F-53240018BBB9_zpsvowaalhx.mp4[/video]

[video]http://vid1350.photobucket.com/albums/p777/Jmurrz/Mobile%20Uploads/6CDF4E7C-28A2-4615-8F56-F2ED298EB04A_zpsbcxpuilz.mp4[/video]

 

[Coxy]

I'd be checking backlash, pinion nut, and both pinion and carrier bearings. A pinion shaft/gear that walks in and out can certainly make that sound. Should be easy to find once you start checking rotational torque with the carrier installed, and removed so you check the pinion by itself. You'll find it. Might not be metal hanging out in there yet, but there will be soon.