Rear thumping turned into a chain rattling noise

[erasedhammer]

So previously I had a thumping noise coming from the back left of my m998 only when I was accelerating. I check the geared hub and changed its oil and checked the gears and nothing wrong.
Couple weeks later I pull it out of the garage after a few days of no driving, and I take it out and now when I let of the throttle I hear a really bad chain rattling noise that worsens when I slow down more.
It sounds god awful and sounds like something is going to rip out of the vehicle. But still drives smooth and no abnormal anything in the driving itself.

Sound is coming from the rear again. Can't pinpoint it but it sounds like it's south of the transfer case at least. When I'm coming to a stop sign this noise wakes up the neighborhood.

I've emailed a few army humvee mechanics and they said they'd need to see the vehicle. Any good humvee mechanics around Seattle? Or can anyone say for sure what might be going wrong?

 

[NDT]

Drain the oil from the transfer case and rear differential and see which one has chunks of metal coming out of the drain hole. Then you will know.

 

[Retiredwarhorses]

Half shaft....

 

[Behr]

Really loose body mount? I had a thumping and rattling from the front and after tightening the body mounts everything is good.

 

[erasedhammer]

Update:

Turns out the chain rattling noise was completely different than my old problem. I was driving back to my house when the rattling turned into a really loose rattling and suddenly there was no output of the transfer case. From what I can imagine is that the high range gear broken in some way so that it no longer made contact. The change in sound wasn't all that bad and didn't cause any other part any damage.
The Low range gear still worked after I pulled over, so I put on my warning lights and drove the last mile home in low range at 18 mph.

 

[Retiredwarhorses]

Thats the same thing you have to do if you loose a halfshaft...but you don't want to be in low, but High lock.
if it were me, I would be check halfshafts...anything is possible.

 

[erasedhammer]

Thats the same thing you have to do if you loose a halfshaft...but you don't want to be in low, but High lock.
if it were me, I would be check halfshafts...anything is possible.

Thats what I thought except the first thing I tried to do was shift into high lock range and drive home but I got the same loss of power to the wheels in high lock as in just high. Low was my last resort and the only thing that worked.

 

[Retiredwarhorses]

Like I said....anything is possible. Plenty of tcases out there for replacement.

 

[erasedhammer]

Like I said....anything is possible. Plenty of tcases out there for replacement.

Is it possible to replace the t/c without removing the drive train? Are the bolts on the top of the adapter reachable when say the drive shafts have been disconnected?

 

[snowtrac nome]

Yes disconnect the drive shafts , disconnect t/c shifter ,and oil cooler lines. I've don it before the top bolts will come out a 1/4 turn at a time but it can be done.