noisy howling

T100 4x4 1994 noise In the drive tran, let off the gas and it goes away. I thing its in rearend ? Any fix or replace with used ?

The pinion nut for the rear yoke could be loose. Could also be the transmission/transfer case output shaft bearing going bad.

Are you positive that it's not in 4x4, they make a good roar in 4x4.

I'd check yer driveshaft to make sure the U-joints are all good... ;)