I have an older Genie Excelerator door opener with screw drive. It would open about a foot and then jam and stop. The original part this replaced had chewed up teeth and was binding in the screw drive. This went right on and works just like it should. Install took about 10 minutes. With the door closed, the lever was pulled to release the original part, I had to loosen two bolts at the end of the screwdrive by the garage door and pull the cotter pin out of the original part to unhook the linkage to the garage. Once loose, I simply slid the old one off. Once off, I slid the new one on and tightened the bolts back down. Inserted the pin that attached the linkage to the door, Installed the pull string, moved the lever up to the lock position and tested it. Worked great.