DHenegan,

There are several moving and rotating parts inside your dryer:

The rear drum rollers,
The motor/belt idler pulley,
The blower wheel,
And the motor itself.

Based on your description "behind the tub", I take for granted, you mean the back of the cabinet, that narrows it down to the rollers and idler pulley.

If yopu can supply the model number off the serial plate inside the dryer door, we can assist you better.

Thanks,
:) :) :)