08 DBL Cab Driveline Noise

I have a 2008 double cab TRD OR with Roughly 85k miles. In the past 5-10k miles I've noticed the driveline seems to be much louder. It seems to be coming from the direction of the rear end. I took it to a private shop and he told me my center carrier bearing was bad so we replaced that (actually replaced he entire drive shaft assembly), but it's still louder. I noticed today that as I accelerate it seems to quiet down, but when I lift off and begin to decelerate it gets louder, like a gear whine. My first inclination is the rear end, but I had my mechanic check the fluid level and he said everything looked good. Any ideas???

 

Nobody???