Question about Sears Craftsman LiftMaster Chamberlain Garage Door Opener Wireless Keypad Model 976LM Security+

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Installed new worm gear, but now i cant get the door down

I installed a new worm gear, and now the chain moves. According to the instructions I need to get the trolley to the closed position before I hook the door up. Even after adjusting the distance and force I cannot get the trolley to move to the closed position, it only moves about a foot down the rail, no matter how I adjust the distance or force. Thanks for your help.

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  • quincyw Jan 09, 2009

    I think I hook it up but wil double check. Thanks.

  • quincyw Jan 09, 2009

    I checked the wire harness and it is connected.

  • Anonymous Jan 12, 2009

    I checked the shaft and its seems to stay perfectly straight when rotatating. What if I take the chain off the sprocket and manully slide the trolley down. Also when I press the opener the trolley starts down (closing) shouldnt it start sliding to open?

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Check to see if the 4 wire harness is hooked up from the limit assy.

Posted on Jan 09, 2009

  • Joseph Chapman
    Joseph Chapman Jan 10, 2009

    Check the movement of the motor shaft. (not the turning of the shaft) The movement back and forth should not be move than 1/32 of an inch


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