Humming and white smoke rear left wheel

There was a loud humming coming from rear wheel when coasting and white smoke from same wheel after driving 30+miles. Was recently leaking small amounts of fluid from left rear axle so assumed this was the problem, so pulled apart and replaced seal and bearing...no more leaking. Now I seem to still be plagued by a loud humming from same side when coasting between 20-35mph and white smoke/burning smell coming from same wheel only after long long drives. Brake pads and rotor look good, even tire wear, could it be a slightly rubbing parking brake? Really hoping its not the rear diff. Any advice would greatly help. Thanks! 99jeep grand cherokeee limited, i6

Humming and white smoke rear left wheel