Sears , the chain is not moving. When open the unit, the white wheel with teeth is not moving. It looks like the "teeth" are worn in some areas. Can I replace the wheel or should I just invest in a new. It is a 1998 unit and has had two cars leaving the garage door every work day for all 12+ years.

Frankly, if it were me I'd just get a new one. The newer screw drive models are more reliable and last longer. I just got the 3/4 HP Chamberlain at Lowe's a few months ago for $199.

You could call around for repair parts, but if the toothed wheel is not turning at all, then it may be an internal problem... so since yours is that old, I'd just get a new one.

... just my humble opinion.

Rick is probably right but Sears always seems to build in a weak link in their product and then seem to sell a lot of those links. That white wheel is a sprocket and is normally steel or brass, unless its Sears. You can get a Sears OEM part at http://www.searspartsdirect.com/partsdirect/index.action if you have the model number. A really good hardware store might be able to sell you a metal sprocket too.