Had a shop check it out but they can't replicate it without it being under load (actual moving). Its louder at slower speeds when you let off the throttle and even louder if your rolling downhill without pressing the gas.

Also got a sunroof leak that I need to fix. How bad is it removing the headliner and reinstalling.

Lastly, can I drive the my DII if I pull the front driveshaft to get rebuilt.

 

#1 Sounds like transfer case?

#2 Tedious and time consuming but relatively straightforward. I've never taken mine all the way out, but I've dropped the front. Panel poppers would probably be very helpful.

#3 You can, but you'll have to lock the transfer case (as long as you don't have a late '01-'03 you can do it from underneath the truck). Do a search.

 

I thought it might be the transfer case but other than a leak on the face plate thats been fixed I can't see anything. It's an 2004 and goes into low or diff lock pretty easily since I changed the gear oil. The mechanic and me both thought the sound was coming forward of the dash but its really hard to pinpoint.