Im having this same issue. It just started yesterday, i searched and searched and haven't found anything yet. I hear the same roaring noise in D first through 2nd, then when it shift to 3rd it goes away. Happened to me on my way home from work. So i pulled the ING0 fuse forcing the tranny into "limp mode" and did just that limped home.
I have changed the Fluid and filter, fluid was a lil dark but wasn't burnt, then took the truck out on a test drive and same issue. Truck shifts fine no slipping or hard shifting, but by way of the noise i KNOW something isn't right. I have a OBDII scanner but the tranny isn't throwing any codes. the only code i have is a P0540 which is Intake Air heater circuit.
Many people are suggesting the transfer case but I have ruled that out because...
-1 when I pulled the fuse which removed power from the TCM and the truck remained in "limp mode" (3rd gear) I never heard the noise, so therefor im assuming its a transmission problem between 1st and 2nd.
-2 I rebuild my tcase 2 months ago, and have since put 6,000 miles on it since then
Im going to try and make a vid and post it, but any help would be greatly appreciated
truck is a 2004 LB7, CCSB, 4in exhaust