Garage Door Drive gear

For Sears Garage Door opener model 139.664053 (may fit others)
Gear part number 81B56

This design was done in solidworks using a helical gear module I found here -
http://www.3dcontentcentral.com/secure/download-model.aspx?catalogid=171&id=428003#0

The file was modified it to replicate the old gear.

Make sure you apply grease when you install new gear!