CHEROKEE4.7

Hi, i have a 2000 jeep grand cherokee 4,7 with 250000 kms, 3 months ago my wheel just started to make a noise like a wheel bearing is gone, today i went to the garage and my wheel bearing is still very strong, no loose... they check everything and they think its something in my transfer case or axle, my transfer case has a very little leak, i tried today to add oil but couldnt find where to add it... otherwise i think it might be a bearing somewhere ? anyone has an idea, even my tire is almost gone like if i used it with a broken bearing.

ol"blue

If they say the hub/wheel bearings are good, it may be an issue with the differential bearings. Pull the plug and check the fluid level. Or pull the cover and check the fluid's condition.
Or it could be an issue with the alignment causing the tire wear.
This shows where to add/check the fluid to the transfer case. It should be at the fill hole when you remove the plug.