Tapping noise from depressed clutch

Here is another one for you guys.  I can hear a rapid tapping/knocking noise coming from the bellhousing area when I push my clutch in and I am moving.  If I am stopped there is no tapping.  The frequency of the noise goes up and down with speed.  It happens whether the engine is running or shut off (coasting obviously).  There is no noise if the clutch is out.

At first I thought I had a bad u joint. But I dropped the front shaft and it still happens.

I have no experience with clutches.  How can I start diagnosing this?  Cant kind a similar situation online anywhere.

Thanks!

One more thing. It doesnt make the noise if slowing down in nuetral with the clutch out. It also doesnt make the noise going in reverse with the clutch depressed.

Does it sound like marbles clanging around in a can?

It sounds like someone put a heavy zip tie on the driveshaft but with a more hollow noise

HMMM
Hollow noises usually have something to do with a drive shaft .
Does it make it in 2 wheel as well as 4 wheel drive.
Is it unusually loud.

yes it is both in 2x and 4x. I pulled the front driveshaft so it is not that... and like I said.. only when the clutch is in. I will try to get some video/audio of it. really odd but doesnt effect the driving/shifting at all.

yes it is both in 2x and 4x.  I pulled the front driveshaft so it is not that... and like I said.. only when the clutch is in.  I will try to get some video/audio of it.  really odd but doesnt effect the driving/shifting at all.

What type and brand of transmission fluid are you using ?

Not sure. Whatever was in there.. It was full up when I got it. Drain and change?

If it's affected by the clutch, that's a pretty good way to narrow it down right there.

Can you try coasting while testing if it makes the same noise with the trans in gear but the transfer case in neutral. That should help narrow it down to t-case or transmission. My first reaction is to suspect some bearing in the transmission.

No noise in neutral. Only in gear.

Does the clutch chatter?
Transmission to bell housing bolts loose, Input shaft bearing in trans, who knows.  

Won't hurt to change trans fluid especially since you haven't yet.
Use GL3 fluid if you can find it...DOUBT YOU CAN FIND IT.
Do NOT use conventional rear end gear oil, or MOBIL 1 gear oil or any GL4 or 5 fluid, as it will eat the yellow metals in the trans (brass synchros etc)

Use Red line MT 90, Pennzoil Synchromesh Manual Transmission Fluid or Mopar fluid for AX15 TRANS.
I have 2 TJs, one of them has 10w30 motor oil in it and it works fine, the other has Redline MT90 in it they are both ax15's.
Use synthetic auto trans fluid in the Transfer Case.

ok. thanks for the guidance. I am leaving for LA for a week so I will report back after that. Have a nice Thanksgiving!

Have a safe trip and enjoy your Thanks Giving.