After removing and cleaning and adjusting by the book, my sunroof would still not operate with the motor but ran back and forth with no effort manually using crank. The motor works fine so suspected the transmission. Removed transmission and found that the motor drive did not turn the the main drive though the manual did! Assumed that the gearing on the motor drive was stripped. As the unit can opened by bending back the locking tabs, I opened it up. I was not able to find any stripped or damaged gearing threads but in turning the drive shaft , the main gear ring did not move . It moved fine from the center shaft. The main shaft has a flat section and there are two special washers that fit over this on the manual drive side. One is concave to act as a spring and apply pressure when the outer cover is pressed into place and peened over. It would appear that the washers apply enough pressure to allow the motor to turn gearing but not enough when the motor has run the roof to its limit.However, there is not enough tension now for that to happen! I noticed that if I left a small space on the opposite side of the gear ring it was tight enough to operate, so, I put the concave washer there and clamped it all together and it worked! There appears to be no information regarding the operation of this unit on the web. It's a Golde 627 647 796 and I was not able to make contact with the company. Maybe they no longer exist. I would appreciate any feed back from anyone re' this . Thanks. Morrelli .