Jeep Repair: front wheel bearings, front wheel bearings, grand cherokee

Question
I have a 1995 Grand Cherokee 5.2 litre all-time 4 wheel drive. The front end roars very loud. I took it to a reputable garage and they rebuilt the axles and put a new bearing in the left front wheel. It continued to roar and he replaced the bearing three times, finally going to an upgraded bearing. It still roars. What can I do about it? It has 130,000 miles and runs great otherwise and my wife really doesn't want to get rid of it.

Answer
The only thing that I know of that will make a roaring sound in the front end of a vehicle is the cooling fan.  If one is stuck on, it makes all kinds of noise.
Have a mechanic put it up on a hoist and use a listening devise (like 3 foot of garden hose) to pinpoint the problem.
If could be carrier bearings in the differential, a pinion bearing and very possibly, the transfer case but one never knows until they can pinpoint the noises location.