I have a carrier 58pav forced are furnace. The unit is loud and vibrating. Does the motor need to be replaced or is there a bearing I could replace? Would it be better to just pull the whole assembly and replace it?

On that model of furnace we have had a lot of trouble with the squirrel cage, it either comes loose at the hub or the fins come loose at the outer part of the wheel.

You have to pull the squirrel cage out of the furnace, this is done by removing the wiring harnesses that are in the way, and then find the two screws at the top and on each side of the cage. With these screws out the cage should pull directly straight out. Then you will be able to see the problem. I bet it is the squirrel cage itself.