Replacement for Liftmaster 41c4220a Gear and Sprocket Kit fits Chamberlain, Sears, Craftsman 1/3 and 1/2 HP Chain Drive Models

I bought this product as my sprocket in a Lift Master 3255 snapped off....I replaced the main gear shaft with the sprocket attached and re-assembled the opener. The chain traveled approximately 24 inches and stopped, it was trying to close the door that was already closed. The MOST important thing to do whenever the chain breaks or the sprocket breaks off, is make certain the opener and the garage door are in the same cycle. To do so, before you re-attach your chain, run the opener, being certain that the garage door and opener are in sync; in other words the door is closed and the opener is also in the closed position , then attach the chain. The kit is great however I spent many hours trying to figure out the "cycle" issue thinking it was something else.....I also replaced the RPM sensor, the capacitor and the logic board which was not the problem. At least I have all new parts in this 3255 and it now works great. I finally realized this from a you tube video and hope this can help others with this unit.

Plate holes are not threaded. Otherwise, these were perfect replacement parts.Oddly, the three screw holes on the plate are not threaded. They must be tapped.I see other comments saying they tapped for 10-32 screws. In my case, the screws were 5mm.Perhaps, this is why they don't arrive already threaded; your needed size varies.I tapped my holes for 5mm and everything went together perfectly.In my case, the old shaft sheared off. This new assembly fixed it.

Exactly what I needed! Motor ran but chain would not move. Opened up the housing and discovered nylon gear drive was stripped. Watched uTube video and everything worked perfectly!

Work great for Chamberlain Lift master Professional 1/3hp Mdl. # 125R. Thanks!

It’s easy. Don’t buy just the gear. I only use the main assembly. I messed with getting the pin out of the old one for a bit, but it just wasn’t worth it for the price of this kit. I already had some taps with the pilot drill attached to the tip from Amazon. They cost about as much as the kit, but they’re great to have around if you don’t lose them. they’re only meant for a quick small project not repetitive use use them two or three times and it was worth it just for a convenience. You should try Mark where the shuttle is on your track. I didn’t count the teeth on the replacement…. But after I had it all set up, I had to loosen the chain again and move it so that it was within the range of the adjustments for up and down. Really not that big of a deal. The holes really should already be tapped though it only takes four or five minutes tops..

Just what I needed. Easy to install. I had to put the garage door down 1st b4 I put the chain back on

Worked great on my 15 yr old Craftsman 1/2 HP opener. Would buy again.

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