Gear and Sprocket Kit

This is a high quality kit that most DIY'ers should be able to use to refresh their garage opener. I only used the work drive assembly from the kit and had excellent results. I found the repair to be tedious but will worth the time invested. My garage door operated so much more smoothly and quieter than before. I believe replacing all the parts would have been even better, but believe this repair should outlive the 25 year old opener.

Clear instructions. Parts fit perfectly into my opener.

The parts were great, but I only used the sprocket + big gear + small gear - the "big ass" piece. I didn't need the worm gear and the other parts in the bag.When my garage door refused to close I figured the big nylon gear had stripped. Drat. Garage door guy asked me a coupla years ago if I wanted him to replace that, and I asked what he'd do. Replace it when it dies. I took his advice. I didn't count on him retiring and the other garage door crew here in Havasu cheerfully bend ya over to do anything.As soon as I pulled the cover (eight 1/4" screws - four coarse thread into plastic, four fine thread into metal) and saw the big gear stripped ordered this kit, which arrived as soon as US Postal found where they lost it - just a day delay. I wish 'Zon wouldn't send stuff US Snail.Anyhow, I watched a great vid on YouTube where a handy guy replaced only the gear - more work, but the gear is six bucks vs. kit is $20. I watched another YT vid by a guy who works on garage doors for a living. Both had great info!Our son did the work, I provided arm-waving. Easy to remove the chain, afix to track, remove two screws from underneath with 5/16" nut-driver, say bad words and remove third screw with 5/16" end wrench. Remove an E-clip and the tiny gear which controls door travel, smack the end of the shaft with calibrated mallet and out comes the old sprocket and gear assembly.After kit arrived, I locked the trolley to the door, and closed the door. We lubed all of the gears with grease supplied. Lubed bearings and bushings. THREADED holes in new cover with 5/16" screws we removed. DO THIS BEFORE installing! Put two of those screws in. Say bad words, and install the third with a wrench. Install lower gear and E clip. Plug it in - no smoke! Whew. Re-attached the chain and locked in place.Tested door twice - ok but goes up too far and not far enough down. Install cover, adjust travel screws a half dozen times while raising and lowering door until perfect. Well, good enough.Watch the vids. The one done by the garage door guy is 45 minutes long, but he'll save you lots of cursing and maybe some breakage. The one done by the handy-guy saved me lots of time. To do this you don't need to remove the whole mechanism or the motor from the mech - as long as your big worm gear is not destroyed.This was pretty easy - about an hour and a half total. Plus an hour to watch the videos. It was easy for me cuz our son did the work. Note that I have most of the tools known to God and man, so we mostly used the right tools, as fast as I could find the darn things<grin>. If you are not handy, don't have a good collection of tools or aren't safe on a ladder, don't tackle it yourself. I had to open the door, move the car, then close the door myself five days, which reminded me of when I was a kid. Glad I now have a robot to do that for me.

First off, you can't beat the price. Good thing, because it's a lot of work. I only replaced the sprocket assembly because the worm gear was still serviceable. It took four hours, and I'm pretty handy with tools. Problem was, the three screws that hold the sprocket assembly flange on the top of the opener were either too large for the tapped holes or the threads were different. I finally went to a hardware store. The only screws that would go in have a slight wobble when installed, so I included a lock nut and a lock washer. I will probably go back and Lok-Tite them to play it safe.The installation manual could include a lot more detail. I got by but I can see where others might get tangled up.Would I use this product again? Yes. It cost me four hours, but saved me the price of a new opener.

Worked perfectly for my Chamberlain model 4200 manufactured in 2000.Like others I only Installed the larger gear. My worm gear was fine, why put in all the extra effort? If it ain't broke don't fix it right?Amazon did ship this loose and my keeper pin was broken on new part. I reused my old one to not have to deal with shipping It back and all that mess.Watch a few videos to pick up a few tips and it's an easy job. Took about an hour.

The gears were delivered quickly. Everything was a drop-in replacement, and immediately put my garage door opener back in service. The instructions were easy to understand, and all the necessary parts were included.

Worked well

This is the second time I've replaced gears on my Craftsman opener that dates back to when the house was built in 1988. The first time was because a spring broke and overstressed the gears. This time was simply wear and tear on a bushing, as described in the YouTube video, which was VERY helpful as I couldn't quite remember how I did it 15 years ago. The printed instructions that were included were for a belt drive unit and NOT helpful and negate the rating for instruction quality.It was easy enough to change out the gear assembly per the video, but the trick is to reinstall the chain exactly as it was. Mine was out of adjustment and drooping well below the track, but if you get it back as best you can, tighten it up per the YouTube instruction, and watch the up/down contacts inside the unit move as it goes through a few cycles, you can figure out how to adjust them as needed. There's also a gear on the bottom of the shaft that drives another gear for the up/down contact switch, and if you move it during installation (which is almost impossible to avoid) it will affect the up/down settings. Again, you'll need to adjust the up/down contacts, but isn't a big deal if you watch and understand how they move and control the door. I think there may be other YouTube videos out there that address this.So after replacing this gear unit and a couple door rollers, lubricating the chain and track, and tightening and lubricating the hinges, my 33 year old garage door is quiet and runs like new, at a fraction of the cost of a service call or replacing the opener.