[EMB]

7 ft high by 9 ft wide, 4 panel metal garage door with a Chamberlin 1255LM opener. The springs are on either side attached to the door with cables and pulleys.

Our door started to jerk from side to side as it was going down, sometimes stopping. Opening seems smother but not quite as smooth as the other door. I let this go on for too long (head in the sand). The gears in the opener failed. I replaced the gears and the opener works well but the door still jerks from side to side on the way down. I have greased the rollers and track and have inspected the rollers and rails for damage. I exchanged the two springs from the smooth operating door with the jerky one but this did not help.

Any ideas would be most appreciated.