2003 4.6L Mustang GT 5-Speed 44,000 mi

Hello, I am having a problem somewhere in rear
of my car. I noticed my car was gradually having a
grinding clunking sound getting louder as the miles
racked up. The noise only appear when I take my
foot off the gas pedal while coasting in any gear, if
I pushed in the clutch it would go away also.
First it wasn’t bad but eventually it sounded as
the whole rear was going to fall apart.
It sounded to me like it was toward the right rear
area. I decided to install the ring and pinon gear set to a 4.10 ratio and had a mechanic do the job. He inspected and reused the original bearings. After he completed the install the noise was still there, no worse or no better.
Could the axle bearing be the culprit?