If the old motor was making the noise then I'm sure it's just because the motor is bad.
You did not post the model number of the dryer, but I have a preaty good idea of what you have.
If you have not removed the blower wheel from the old motor yet, remember it has left hand threads.
I would replace the motor and give it a try.
Let us know how it goes,
Thanks,
John@FreeApplianceRepair.com
www.FreeApplianceRepair.com