Yes and maybe.
If you open unit, usually fan motor is plugged in, and motor is removable with bolts.
The problem is finding new fan that fits same housing without spot-welding and drilling.
I did google image search for "replacement vent fan motors" and results show choices.
For example Nutone:http://nutoneproducts.typepad.com/nutone-products/nutone-bath-fans/page/2/
If you can locate same brand vent at local box store, you can use parts from new one to repair old one without project of replacing fan housing.
20 years ago, motors went to electric repair shop and they rewound the motor.
But today, motors are landfilled or shipped overseas for recycling.
All costs are energy, and right now, cost of re-wind is more than buying new motor, or new vent.
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