Rear end noise

[Rod123]

Have noise in rear end loudest under load diminishes when letting off accelerator nearly non existent when shiffted into neutral. Blazer is '95 with 125,000 mi. What bearing is likely culprit and what is likely cost. I suspect I'm not first with this problem. Thanks

[comp]

check and/or change diff gear lube first

[Rod123]

Gear lube previosly changed and is full with correct type.