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

Great packinage and great product. I installed it without any issue and it worked! You'll still need a great YouTube video to walk you through the installation.

The product arrived quickly and fit exactly as the 30 year old unit. I would advise installers to run the 3 screws that attach the new gear system to the unit on your bench first as the threads in the housing needed to be tapped by the screws as they were rough. I initially didn't do this and couldn't get the screws started. I brought the unit back to the bench and tapped the threads with the screws. This made all the difference and then installed easily. I used the grease that came with the kit. It worked perfectly.

The chain drive gear on my Chamberlain 1/3 HP garage door opener broke. This was a perfect fit as a replacement. Took less than an hour to remove the old one and replace the new. The kit not only comes with the drive shaft with the worm gear, but also included the worm shaft if yours is worn. An easy replacement all around. And the included grease is in a sealed tube with a cap, instead of one of those packets you need to cut off and cannot reseal. As others mention, the top plate is not tapped for the small screws (which you must use the originals). Before installing, just carefully screw one of the existing screws into the plate from underneath to create threads for when you install it. This makes it much easier to install the bolts once you've put the shaft in the opener. After having just installed this, I would highly recommend. 10 out of 10.

Easy install! Did what described, comes with many extra parts as well!

I was meaning to change this on my opener from the late 90's but it failed before I could be proactive about it. Symptom was that the motor would run, the door would go up a little bit then stop. The door would not go down. Opening the cover to the opener, it was full of plastic shavings from the old gear. The old gear was almost worn smooth after decades of use. I didn't actually need most of the items in the kit, just the main gear piece and the grease. My worm gears were still in good shape, so I just reused them. I'll keep the pieces around just in case. Installation was easy enough after watching a couple of YouTube videos. There is one bolt that I needed to use an open end wrench to remove (and reinstall), just like the videos told me. That was the hardest part. I had a little trouble figuring out how to position the chain and the top and bottom door position. Another reviewer pointed out that the gear is a different size and that's probably what my problem was. After some trial and error in adjusting the postion of the top and bottom for the opener, I figured it out. Also note that in order for things to work correctly (apparently), the chain needs to be hooked up to the opener. I tried just running it without the chain attached to make sure that it would obey the top and bottom positions and it didn't. Once I connected the chain, I was able to start testing. As I said, there was some trial and error involved. Luckily, the errors didn't cause any damage. I know a lot more about garage door openers than I did before making this repair. As other reviewers have said, if you are considering buying this, you can probably capable of making the repair. I'm not particularly smart or handy and I did it. It was less work and less money than buying and installing a new opener.

After 29 years of use. The bushing for the chain drive shaft wore out. (Lack of maintenance) While I was mentally prepared to replace the whole opener, the handyman in me decided to see if it could be repaired. I was surprised to find this whole assembly for MUCH less than a whole new opener. After some disassembly, reassembly and adjustment, my opener works like new. HIGHLY recommended.

I got this because the shaft bushing wore out in my 22-year old opener. It fit perfectly and turned out to be a very easy repair. There was nothing else wrong with the opener and this fix was much faster, cheaper, and easier than installing a new door opener.

I'd had a garage expert out to adjust my door opener, and he told me it was going to fail and I would need to replace it. Fast-forward a few months and the drive gear sheared off, so he was right in that regard. I looked up the parts in the back of my manual, and it looked pretty simple if you know one end of a screwdriver from the other. I ordered this kit, with same-day delivery it was less than USD $30. Parts were as described and pictured, fit perfectly in my LiftMaster 3255-2. It has the main drive gear assembly I needed for my repair, plus others I chose not to install but could (worm gear, bushings, shear pins). I was able to complete my repair in about an hour, which included repeated times up-and-down on the ladder because of dropping screws. Would have benefited from some basic instructions on what was provided, and installation steps. It's not just drop it in and go on your way, my opener has internal mechanical limit controls. I needed to get the opener to the "closed/down" position while the door was closed, and then install the chain. It wasn't difficult, but you should be able to figure out how to do this with your particular opener.

予定到着日より１０日以上遅れて到着しましたが、無事配送されました。 取り付けのねじ部がタップが切られていませんでした。 なお、ネジはインチネジ （元と同じですが）でISO規格ではないので注意が必要。

Everything worked out. Repair was easy and parts for as they should.

te ahorra mucho dinero al tener esta pieza como repuesto, se mira de la misma calidad que la original , ahora hay que probar cuanto dura...

El producto cumple con las expectativas requeridas, un poco complicado de reemplazar por la parte que originalmente se daño, pero con un poco de paciencia, quedo mejor de lo esperado. Viene con los reemplazos necesarios para hacer la correcta colocación. En caso que no tengan la paciencia para el cambiarlo es recomendable contratar a personal especializado, ya que en algunos momentos si es tedioso estar maniobrando en las alturas (donde comúnmente se encuentran los motores), ademas que si requiere sapiencia el ajustar los máximos de apertura y cierre.

Relatively easy to install with online videos as support. Works well, but still noisy. Think I might need to change the chain.