Original post by: dkupy1 ,
May be bad news. The differential (rear axle) might be going bad. I had same symptom in a 2002 Ranger XLT (163K miles). Pulled cover off the rear axle and some gear teeth were chipped and axle had excess play. Replaced with a used complete axle (80K miles) now quiet. $500 parts, $600 labor. I'm trying to get 250K out of the truck. Engine is solid.