I bought a Genie H4000A-2 in 2007, which is a screw drive model, hoping it would be more reliable than the chain types. Well, this one failed. It’s a 3 piece screw, which is the source of the problem. The screw drive sections are held together with these collars, and the collars are kept in place with crappy little retaining clips. And to add insult to injury, they want to sell you the collar and clip (19863R Screw Drive Clip and Collar) for about $8 (that includes $5 shipping, but the Overhead Door company here doesn’t carry the collar/clip kit, but they sure as hell wanted to sell me a whole new opener!).
Anyway, in this video I show how not to buy the $0.02 part for $8.00. Instead, I wrap some copper wire around the shaft and solder it to itself. Then I install a new carriage ($13.50, delivered off Amazon – Genie 20414R Carriage for Screw Drive Operators).
Avoid multi-part screw drives!