Had roaring noise in front end that stopped when steering wheel was turned to left. Mechanic 1 diagnosed problem as a left front wheel bearing and the bearing was replaced. Noise continued. Mechanic 2 diagnosed problem as right wheel bearing. Mechanic 1 disagrees stating that he removed the right wheel bearing and it turned freely when it was removed from vehicle. He feels that the problem is a bearing in the front differential and states that it will be expensive to replace because it is necessary to "drop the front end."

I know that these wheel bearings are in sealed units. Is it possible to determine if they are ok by rotating the unit after it has been removed from the vehicle?
In other words could it be the right front wheel bearing?

Is it necessary to drop the front end to replace a bearing in the differential?

Would the noise cease by turning to left if it was a faulty bearing in the front differential.

Am confused.

I would be glad to make a donation but I don't use my credit card on the internet. However, I will be glad to send a money order.

Nelson