Glad I was able to repair my opener rather than ...
349252
Glad I was able to repair my opener rather than having to replace the whole thing.  This kit included the nylon worm gear that wore out on mine, however I replaced all the parts, even the ones that didn't appear to be worn.  I think this opener is going on 20 years old now, glad I can still get parts for it.
3695756
This kit worked perfectly to repair the top sprocket/gear that had snapped off on my 1/2 HP LiftMaster Chamberlain garage door opener.

I only needed to replace the main sprocket/gear on my opener, as the rest of the parts looked like they were in pretty good shape. If you're at all competent mechanically, you should be able to replace this gear in under 1 hour and without having to remove the opener from the ceiling.

You do not need to remove the motor as described in the instructions that came in the kit.
1) Remove the front and back of the opener. You might be able to leave them hanging by their cords but you can disconnect the cords if they're in your way.
2) Remove the bottom/sides piece of the opener.
3) Remove the limiter assembly under the main gear and sprocket (it has 2 plastic screws that normally go to the side of your opener). There are two clips that are squeezed (one of mine had to be gently pushed on by a screwdriver), and then the piece rotates down and the slides out of the third mounting spot.
4) Use a socket or wrench to remove the 3 screws that hold the sprocket/gear assembly in place. These gears unscrew from below the top plate of the opener.
5) Remove the small, white plastic clip on the bottom of the existing sprocket. The small white gear should now slide off, and the gear/sprocket should be able to be lifted upwards out of the opener.
6) Remove the same small white clip and small white gear from the new sprocket, grease the new sprocket teeth with the enclosed grease tube. 7) Drop it in from above, install the screws that hold it in place, and reinstall the small white gear and plastic clip.
8) Put everything back together (limiter assembly, replug in electrical stuff, put covers back on).
9) Loosen the chain tensioner. This tensioner should be up near your garage door.
10) Test your opener without the chain on it, make sure the garage door is closed, that the chain is engaged with it, and that the sprocket has turned to the closed position (usually after it has turned clockwise if looking at it from above).
11) Carefully put the chain over the new sprocket/gear. Try to get both sides of the chain equally slack. Have some paper towels near by as this is pretty messy and don't pinch your fingers!!
12) Re-tighten the chain tensioner to the proper tightness. On my opener with a T shaped bar, this meant the chain's sag should be about 1/2" above the bottom of the T bar.
13) Open and close the door and adjust the open and closed spots using the screws on the side of your opener. Adjust the opening and closing force according to your opener's instructions.
4158242
Once we figured out what the problem was (slipping carriage), this was a quick fix (relative to replacing the whole system).  Seems to be working great again.  Just make sure you're ordering the right part as they mostly look very similar.  Our opener is 20 years old and uses a magnetic sensor.
4516568
I purchased this to replace the opener for my 2007 Toyota FJ Cruiser. After years of use, the part of my original opener that holds the key ring broke (which seems to be a common problem and thus the need for this product). It is important to understand that this is just a shell that contains the buttons but not the electronics to make the opener work. All you have to do pry open original opener with a screw driver, take the electronic board and the rubber bladder out of the original opener, put it into this shell, and close this new shell. It took about 2 minutes to do (mainly because I didn't put the rubber bladder into the new shell the first time and had to open it back up). It functions just as well as the original opener. The only differences I can tell between this and the original opener is that it is missing the Toyota logo and it is flat black instead of glossy black. Good quality product that should last as long as the original.
1599410
The replacement gears for the liftmaster garage door opener worked great.  This is the second time I have ordered this product and was able to fix both of my garage door openers.  The openers are over 10 years old and the top gear on each has snapped off in the past year.  The installation was simple, just a long process to get to all of the screws that hold everything together.  This was a lot better than buying new openers or paying for someelse to fix them.
3847102
I had an older model Chamberlain 1/2 hp opener that died in a recent lightning storm.  I ordered this to replace it and was extremely pleased that it was a direct replacement unit.  I didn't have to install a new chain or track.  Just took the old head unit off and popped this one in.  What a time saver.
4927163
Fixed the problem . . . Nice having a working garage door.
3336303
Fantastic opener, I wish I had ordered this year's ago.
4774420
This part and 15 minutes of work repaired my 2010 Kenmore Elite Ultra Wash dishwasher (model 665.1312*).  For those of you who are not confident about repairing a dishwasher, read along because I wasn't either but this part was easy to replace.

After two years of stellar cleaning, our dishes suddenly starting being consistently dirty after the wash ended.  Since the problem occurred spontaneously and we had previously had great performance, we knew something was wrong.  Some online research suggested that the problem could be that we didn't have enough water running through the cycle, and sure enough if we opened the dishwasher 10 minutes into the cycle, there was only a little water at the bottom of the washer.  Normally the water should be about 1/4" below the heating element.  Online forums said that problem is usually fixed by replacing the inlet valve.

I'm not terribly mechanical but I figured I could at least take a look at my washer.  I unplugged my washer and turned off the water to it.  I removed the screws on the access plate at the bottom of the washer, and I opened the door and removed the two screws at the top of the washer that attached it to my counter.  Then I pulled out the washer and was able to see the inlet valve on the front left side of my washer.  I unscrewed the hose coupling, unscrewed the hex screw that held the inlet valve to the washer frame, and slide off the washer.  Finally I gently pulled off the electrical plug to the valve and took off the rubber hose.

The part number on the inlet valve was this Whirlpool inlet valve model, so I order this from Amazon and replaced mine.  I hooked everything back up and my water level is now correct and my dishes are clean again.

I ordered second day air and placed my order at 10 am CST, and my package arrived the next day!  My local plumbing supply didn't have it in stock and were more expensive anyway (even including Amazon's 2nd day shipping and sales tax.)  Gotta love Amazon.
2587915
This fixed my wife's Honda van door that was not opening automatically.  It took about an hour to change it out.  The worst part is getting the cable back on the new roller.  other then that it is pretty easy. .
2588726
Bought this for my Kenmore Elite Dishwasher.  The corded plastic piece that connects to the door hinge had broken on one side and was getting ready to go on the other.  Purchased this set and the cord's fit and worked perfectly.  I did not use the pulley bracket.  It looks like the same general size, although it on of the pulleys was more egg shaped, as opposed to being round on the factory part.  I doubt that would have been an issue though.

The actual repair was very easy.  I pulled on the dishwasher and it was obvious what had broken (especially considering the door wouldn't latch or fall correctly).  Had my wife hold the door closed while I hooked up the cord.  That may require two people if you're not strong enough to pull the spring with one hand AND hook the cord to it.

Door is working better than it has in a long time.  Doesn't slam down when you open it and latches well.  Apparently it had been going bad for a while and I didn't realize it.
559616
It works and it was easy to install. I was glad our old opener was around (broken) therefore I was able to copy the setting.
2355078
Restored my garage door openers to "like new".  Can now start the garage door opening before hitting our rather long driveway - a  great improvement over opening ten feet out or not at all.
3084064
I ordered this "gear & sprocket assembly kit" on Thursday night, and was delivered on Saturday 5:30pm, just-in-time for me to work on fixing my garage door opener. Kudos to Amazon, seller Sanford and Sons? Overhead Doors, and Ensenda Delivery Service. Somehow they all realized how much I needed this part desperately, so I can repair it on the weekend.

All reviewers here were helpful with all their inputs on how to fix it, what should be done and what to avoid.
I started working on it at 6pm and about 4 hours later, my garage door opener working again as good as new. Of course, within those 4 hours, I have to take dinner break, bathroom break, etc. What took me so long was to clean up all the "shaving" / "plastic snow" left behind inside the unit. Blow it with air compressor, clean up the grease gunk. And you work on a small and delicate unit. You proceed carefully and slowly.

I have to inform the manufacturer that one of the tiny screw (part C) to secure the collar part A or B (refer to picture 3 and 4 on manual leaflet) to the shaft failed. It looked like its thread became dull. I have no idea whether the thread on the tiny screw or the collar that became dull/failed. So I re-used the old collar and screws assembly. The grease provided was more than enough. I still have 1/4 or so left over for future re-greasing the gear assembly.

A little bit of filing the burrs on the shaft is necessary in order to take out the collar A or B easily. It will glide effortlessly once you file the burrs and the end of the shaft.

In all, it is not hard to do it yourself, just take your time on weekend, follow the instruction on manual leaflet provided, and also read tips from reviewers on Amazon.
3723767
When the main nylon cog in the Craftsman garage door opener split in two, I expected the worst -- time to replace the opener.  Had I known that the cog was made of nylon (like others realized), I would have been greasing it annually.  Doing so is a matter of removing the cover with a screwdriver and squeezing some grease in the teeth of all the working nylon parts, simple.  Worth it compared to the ~4-hour, two-person job of pulling the opener apart to get at innards you need to replace.  That the cog would dry out and snap after at least 15 years of no maintenance...go figure!

If you're guilty of similar neglect, this is the perfect kit to save yourself a few hundred dollars and the perfect project to put your dad/close friend to work.  Even better, you're left with extra grease (enough to grease your other opener and the one you're repairing this time and a couple more later).

There were some frustrating steps, though.  Removing the pins wasn't too tough if you have a punch.  The part that drove us crazy was how to get the (don't remember the part name) almost-round, metal part with the notch off the stem where the worm resides.  In our case, it didn't simply slide off (probably tight from the metal-on-metal contact/oxidization of 15+ years).  If you get the same, hair-brained idea to drive the stem out with a hammer/hammer-punch combo (hopefully your solution is more elegant), be prepared to lightly file down the edges on the end of the rod where you were making contact; otherwise, it won't come off.

Also, after you get it all back together and are making the lift adjustments with a lot of opening/closing, don't be surprised if the opener suddenly won't respond.  Relax.  It's likely not broken again, just overheated.  Give it a few minutes (apply beer, take deep breaths, you don't have to start over), then finish your adjustments.

Lesson learned: Keep the working, nylon parts in the garage door opener well-greased!
4589125
This worked with my old opener no problem.  It's not fancy, but it's been a reliable option that was significantly less expensive than what Sears wanted to charge me.
3834147
My son-in-law locked the garage door one day, and my son tried to use the opener to open it the next day.  The box made an awful noise, the chain came off, and the sprocket on top was at a weird angle.  Ends up the gears were still good, just the plastic gear case feet broke off where the gear case mounts to the frame of the opener.  Swapped the gears over to the new case (held in by a snap ring), installed the new case with the four included screws, and the opener works great again.