What would cause a wo wo sound 4wd Mariner?

A "wo wo" sound in a 4WD Mariner could be caused by several issues, including worn or damaged wheel bearings, a failing differential, or issues with the transfer case. It may also arise from tire problems, such as uneven wear or improper inflation. To diagnose the issue accurately, it's best to have a mechanic inspect the vehicle, as these sounds can indicate potential safety concerns.