The below video should give you the basics about motor replacement.
Dryer Motor (part #279827)-How To Replace - YouTube

Note: That often the blower is seized onto the motor shaft and has to be destroyed to get the motor off.

[COLOR="Blue"]Is there some way to check out the motor bearings?[/COLOR]
I do not have a procedure for this.
Perhaps a search on Youtube might pop something up.
You say the spin is OK.
Now move the pulley end side to side and up and down to see if there is any slop in the bearing.
Put pressure on the pulley in the direction that the belt puts pressure on it. Then turn it slightly back and forth. It should be nice and smooth. If it feels gritty the bearing is bad.

Below is a link to a good site that may be useful to you.
http://www.applianceaid.com/whirlpool-dryers.php
Take a look at #26 especially the "motor endbells" link.

You are welcome

And thanks for getting back to us. Now when others search for a similar problem they will see what actually worked instead of just suggestions about what could be the cause.