Craftsman (LiftMaster) garage door opener issues? 

Just finished following your instructions successfully .. Only $15 out pocket.....Well done and THANKS....

i began troubleshooting the repair by removing the whole gear/motor box since i started before finding the video on youtube. i ordered the part through sears, received it in 2 days. i never wouldn't figured out how to remove the shreaded gear without this video. the job took me about 2 hours total, i really took my time since i'm not the most handy guy. this video saved me both $$ & time, i really appreciate it Kris !

Great tutorial. I just bought a whole new unit $$$$. After watching your walkthrough, I’m Returning it and replacing the gear. You saved me a lot of time and money. Thank you

Thanks for the helpful vid. My moms door just went down and she was about to buy another one. I told her to hold till I could look at it. Saw that gear was worn, found your vid, saved her some money. Jesus bless you, take it easy.

I followed your great instructions two years ago. Worked great! The hardest part was removing the pin from the gear. Now, i'm about to do it again on the other opener. thanks again.

thanks for the video. no one is happier than my wife! got the whole job done for less than $20

I can't believe I found this video. This is the exact door opener I have, but my gear is in much worse condition. I am going to order parts today. My door does not open easily manually so I want to fix that before re-connecting to the garage door opener. Thanks for the video - this will make this job much easier.

This was super helpful, thank you! The replacement part arrived at my door at 9am and I had the door working by 10am. The one thing I would add is that if you don't have a vice, I'm not sure how you'd get the pin out to remove the old gear. In that case, be advised that you can just buy a whole new sprocket/shaft assembly with the new gear already on it for just a few bucks more. Search Amazon for part number 41C4220A. Even if you do have a vice, the time saved might be worth it to go that route instead. Also funny that looking back through the comments it seems to be all of us Minnesotans that are having this problem this month. :-)

My gear was stripped and is on the way here. Watching your video is helpful. Thanks!

I have a similar Craftsman opener, cracked open the back panel and found the same gear completely stripped off. Thanks so much for this video, didn't know I could order the individual parts from Sears. Saving me a couple hundred dollars from replacing the whole unit!

Thank you for this instructional DIY video . Not only did you keep it simple & straightforward you saved me and my Family hundreds of $’s … 👍👍

Thank you. Kris. Mine went out 30 minutes ago and I was livid. Now I see it's something I can fix. Thx again!

Kris - Thank you very much! I had looked on Amazon for the white plastic gear and an Amazon review sent me to your video. The whole Pilot garage door opener cost $370 in 1999 and the company that installed the garage door probably would have wanted to replace the whole unit and charge $100 at least for the service call. Instead of spending upwards of $500 for a replacement unit after 14 years of operation, I bought the gear and grease on Amazon of $14 and saved over $400. Great how-to video!

Kris, thank you so much for putting up this video and it gives me the confidence to do the job myself. In order to make sure there will be no surprise, I have read most of the comments for additional tips. I thought it would be a time saver if I summarize all the tips over the years here. Plan on 30 - 60 minutes for the job. Time depends on how detail you want the job done. Count on doubling the time if you want to change the worm gear. Before disassemble, you would want to mark the chain position, clamp down the chain trolley, and mark the top cover orientation. This will save you time on adjusting the limits. Loosening the chain tension screw will make your job in detaching the chain a lot easier. Cover Screws for the sides and front/back are different. Be careful when you put them back. Taking the back cover off and detaching the circuit board will make it easier to access the inside, but it's not a must. Remove the hard to reach screw for the main gear assembly first. You won't need to struggle if you have a 5/16" ranch. You don't need a vise to remove the pin from the main gear shaft. What you need is a 3/16" pin punch and then the job can be easily done by propping the shaft across two pieces of 2x4's or something like that. Putting on tons of grease will be pointless if the debris is not clean out from the worm gear and surrounding areas. The debris will shorten the life of your new gear. Your gear kit will come with instructions. Couple that with Kris's video, one should be able to tackle the job successfully. There are three more RU-vid videos on the same subject and explain the job from different angles. These can fill in the gaps if you are not sure how to mark chain position and clamp down the chain trolley with a visegrip. They were by AdamDIY, Paul Gatekeeper and All-Pro Quality Garage Doors. Thanks guys for helping me out with the job. Hope my summary helps others

Hey Kris, thanks for this video! I ended up having to take the chain off, but everything went smoothly, and I was able to adjust the travel and all was good. My garage door repair guy said, "Well, you'll probably need to replace the unit, so all said and done, it'll be about $650.00" Thanks to you, it cost $11.75, an hour of work, and a cold beer. Outstanding video. Thanks!!

Thank you! Just fixed my garage door opener, with your help. Didn't want to have to call or pay for a Sunday repairman

Thanks so much. This will be second time to do this, but at 24 years old, I am thankful for the long life Sears opener.

THank you SOOOO MUCH for posting this video. I was about to buy a new opener thinking my was done for when I found your video as a last resort. Got my parts in a few days and completed the job in an hour. Hardest part was popping the roll pin out, otherwise it was a piece of cake like you mentioned in your step by step instructions. THANK YOU SO MUCH for saving me money!

Thanks for keeping the video to the point. I had to replace the sprocket as it had snapped right off the shaft. The only problem I ran into was trying to figure out which part # to buy. I have a Sears Craftsman Model # 139.18856 The replacement part is 41C4220A ... this includes the sprocket and the gear already assembled so all I had to do was slide out the old and slide in the new. If you are having trouble finding which part # you need, just call Sears Parts and they will sort you out.

Thanks Kris. Followed these instructions right down to using the nail punch and they worked perfectly. I also found if you remove the rear plate with the circuit board (but leave all the wires connected), you can take a little string and tie that up and out of the way for MUCH easier screw access. Appreciate you posting this!

Thanks for the video. I ordered new assembly (Liftmaster 41c4220a Gear and Sprocket Kit) for $20.60. It took me many hours but I got it installed. My garage door opens much more smoothly and quieter.

Thanks for the clear video. I had a limiters problem but the gear was in excellent condition, so, here is the story: I had my Liftmaster 5580 ( from 2006) "fixed" by technician. The "fix" hold for 1 day... The Tech guy said that my gear was gone, and it will cost 350$ to replace it!, he also brought a new LM80 for 820$! I didn't agree of course. So, I looked for videos on RU-vid and thanks for all the good people that filmed their fixing I was able to understand what is going on. First, I opened the motor back door and I looked carefully. My gear was as new! Now, my simple idea is to bring the the up and down limiters to their correct place by visual inspecting inside the motor and manual rotating the screws. I disengage the gate and put a mark on the rail holder of the trolley, once, for the gate is in closed position and another mark for open position to the height I want. Then I engage the motor to a learn position (2 clicks on the orange square button on the back of the motor, the the small light is blinking) The advantage at this mode is that every push on the remote controller is either moving up or down, so I can adjust the trolley position. So, I brought the trolley to the up position and then my simple contribution to the solution is to rotate the up limiter with a flat screwdriver until its metal contact is touching the metal in the middle wide limiter gear, while I am with the motor back cover open so I can see exactly the movements and where and how much I should rotate (no more guessing...) The same I did for the down position. Then I engage the trolly to the gate, start another learning mode and there it was fixed! (at list 2-3 times up and down with learning mode so this motor can adjust itself to the force required. (The blinking light is stooped when the engine did it learning job successfully). I hope this will help someone with the same annoying problem.

Exactly what I need to do , Just wanted to see how it is done before I tear into it. Great video and actually looks easier than I expected, thanks

I just watched this video and replaced the gear in my opener. Doesn't get much easier!! After I got it all back together, I did have to adjust the up/down travel as well as the closing force. Thanks for the easy to follow tutorial.

Thank you. I saved and used this video 3 years ago to fix one door and the other gear just went today! Will be using this video again. Ordered 1 new worn gear for $6. You saved me alot of money once again. :)

Great video! I was going to purchase a new garage door opener but thanks to your video I saved $175. Thank you!

After my son and I both smashed our fingers by opening the door manually, decided to fix it! My son came across your video and was able to fix the door in a short time. Thank you Kris! You are the man!

Kris....you just saved my a lot of money buddy! After getting a quote to replace the entire unit with labor I was looking at upwards of 400.00 bucks. I watched your video last night and decided to investigate by opened the unit to find the gear had been ripped to shreds just as you said. I went on Sears direct ordered my part and picked it up when they opened this morning. And now my friend I have a working garage door again!!!! Had to replace the safety sensor as well as one was no longer lighting up and the door would not stay down. Altogether I spent around 50 bucks for parts. I cant thank you enough for making this video

Just want to thank you Kris for this instructional video .. I today replaced gear per instructions and are back in business again at a parts cost of maybe $8.00, and a couple of frozen fingers

Your instructions were very clear and easy to follow. The only difficulty that I had was removing the hollow bottom pin from the drive gear, as my nail set enlarged it, instead of pushed it. Once that was done and I reinstalled everything, I did need to reset the travel switches on the door, as you mentioned. That was likely due to my loosening the chain, in order to place it back on the sprocket. Thanks! You saved me a few hundred on a new opener.

Cheers. Wouldn't have attempted without watching this first. Hardest part was getting the damn screws out and the pin without a vice. Ended up putting the screws back in from the top rather than the bottom. Gordon, UK.

Awsome video, very helpful... my garage door stoped working and was making a griding noise inside. I panicked i thought it was going to cost me a fortune but because of this youtube video I ordered the part and replaced the gear myself.. the only mistake i made was i forgot to mark the chain so i have to play with it and found the right placement.... you are the best man... Great job with this youtube video. you are a money saver. Thank you...

Awesome video Kris ...! You make it look so simple and following your steps - it really is - took me about 35 minutes and all works great - thanks....!

Excellent how-to! No wasted words, very clear images and explanation. Sears sells the gear package for $40..I ,know how some got it for $8.oo, but $40 is less than a new opener assembly. My opener is 34 years old...

Great video! No parts available in the UK for my door, but found a part delivered to UK for $35. Much better than the $500 repair quote we were given!

Thank you - you saved another one. :-) I will say that I battled for several hours stuck at the off camera moments; trying to get the gear assembly to come out (about 15 minutes), 40 minutes or so fighting the infamous pin, another 15 minutes battling the assembly going back in and my worst was a couple hours battling alignment of the screws once the assembly was back in. If I had to do it over again I think I would buy the sears part that includes the gear already on the assembly for about $15 more to avoid the pin issue. And if you are working this repair solo, loosen the chain (a lot) otherwise its almost impossible to get everything aligned for re-assembly due to the tension from the chain pulling the assembly back. So I might win the award for the slowest repair - but still great its all back and working. Thank you!!!

Great video/Audio. My opener gears looked just like your. Thanks to your video i don't have to ignore the problem anymore or buy a new opener.

I had done this before but I removed the whole opener and fixed in on the bench. This was a lot quicker & easier, thanks for the video.

Thanks for that.I was about to go buy a whole new opener but it was snowing real hard tonight and thought I would see what was on RU-vid and found the exact problem .Thanks

Thank you so much for this video, I had the exact issue you have mentioned in this video. Without this video, I would have to call someone who probably would have ripped me off as I wouldn't know what was happening with the garage door opener. I spent $10 on the part and went step by step on your video and got my issue resolved and working again!!! Taking the pin out of the spindle/gear was truly a pain and the bench vice is very much needed to tackle that part.

Amazingly accurate video. You are correct on the unlikely need to replace all the other hardware, including the worm gear. I cleaned the hardened gunk out of the worm gear and it looked like new. The drive gear appears to be made out of a much softer nylon, and as a result gets chewed up quicker. This is a common sense approach that is much easier to do. Thank you very much for posting this video. I picked up 2 drive gears for 8 bucks shipped on Amazon. My 20 year old opener works great now.

Thanks so much! Took me about and hour all said and done. I found the 3 5/16 screws to be the biggest pain.

Just got back from Sears Parts. They also have an assembled unit for $10 more than just the parts kit so I got that to save time. Thanks to your helpful video, I will not need a new unit!!!

Somehow I ended up here watching your video. I would say that anyone who watches your video should be able to replace those gears easily. If they cant seem to accomplish this then it's probably time they ask a neighbor or friend for help. Very well done! BTW this is first time I have ever complimented someone on a video that was very well produced, because most aren't.

After obtaining the replacement parts,I watched the video. I avoided trying to figure things out and was able to replace the parts quickly. Thanks for an excellent presentation.

Really appreciate your help with this video. I was googling to see if plastic gears are common in openers, to essentially purchase a new one. This video gives me the confidence to attempt a fix first.

Kris, thanks for the excellent video. Repair cost was about $12 with gears from ebay. One note - when reinstalling the drive gear, the DIYer should make sure the top mounting plate is oriented so the two rectangular slots for the sprocket cover are to the front and back. Otherwise, you may get everything put back together and find the sprocket cover won't snap in place.

Just used your video as a guideline to fix my garage door opener. Removing the pin that holds the gear in place and then putting the pin back in was by far the most troublesome. Thanks for sharing this DIY vid.

I know some one who called on me to fix his garage opener. This helps a million! Thx

Thanks a ton. Your video was right on. The tough part for me was getting that little pin out. Insane. But once I got it out I was home free. Thanks!!

This is so much easier than other videos on doing this, I didn't want to have to take the hole opener down off the celling and take it all apart

Great video. Thanks. Allowed me to change the gear myself. Works like a charm now. The only step missing was how to remove and put back the chain around the gear on the motor. That cost me probably 2 hours, on and off. Some people may think it is obvious, but the video does everything step by step except that part, so it threw me off quite a bit. That is the only thing missing.

Thank you so much for all your suggestions- We figured out that we just simply had overworked the motor while trying to adjust the up and down process. I tried opening it with the auto controls and it worked and I think we are back in business- I thank God for wonderful people like you- you saved us so much money in repairs- Again I can't thank you enough! God Bless!

This worked great for me. I bought the single drive gear Part # 41A2817 and a tube of lubricant. I didn't have a vice to use for the pin extraction so I made a template/jig out of wood to perform the procedure you discuss about 5:30 and begin at 5:40 in the video. The door works well now - quieter and smoother.

Man, did you save me! I had the exact same issue...stripped gear. 27 dollar part from Sears and it's working great. Only difference is the Sears part came already assembled on a new shaft, however the threads needed to be cut on the new housing...simply ran the screws through the holes twice and it cut the threads just fine. THANK YOU SO MUCH!

This video is legit, it was exactly what I needed to do and it solved my problem. Thank you! The toughest part is definitely taking out the three screws. I also ended up using a 3/16" pin puncher and laid the shaft across two 2x4s to hammer the pin out.

I was able to fix my problem in half an hr. I am mechanically inclined so I wasnt scared to put my hands in here. Like this gentleman in the video I also did not need any of the extra parts that came with my order from Amazon.com. I simply followed the step by step directions on this video on how to uninstall the sprocket part then the rest was pretty self explanatory. I didnt even need to finish the video. Thanks for this video

awesome video and instructions Kris, me and my 17 year old son had just about given up on fixing this and we were ready spend almost $300 on a new opener and the installation, then we came upon your video and an hour later we had our garage door and opener running smoothly again! Thank you sir!

Thanks! Just took apart my opener and found this gear shredded to pieces. I was intimidated at first by the work involved with replacement at first glance, but after this I'm confident enough to order the part and replace it myself, saving me a ton of money!

I love RU-vid. Just had my opener stop working, opened it up to see a bunch of shavings like you. It's the exact same problem with the exact same unit! Love that there's a video showing an old opener like mine lol

Great video! Fixed mine good as new because of your great camera views and commentary. Thanks!

Fantastic video!!! My opener stopped working today and I just finished taking the cover off. Everything looked exactly as shown in your video. A little intimidating I might add. I will now track down some replacement parts. I don't anticipate any problems now. Thank you very much.

Four people think Tab A goes into Slot B, and therefore couldn't follow these *excellent* and well-documented instructions.

Video was spot on.. instead of changing the gear.. i just ordered the gear and shaft makes this much easier. Only thing i would suggest is to loosen the chain a bit to make setting screws back in a little easier. I also had to adjust my travel after this fix. Thanks a lot this video helped.

Great job! Took me a little longer since I replaced everything that came with the kit. This video was exactly what I needed to give me the confidence to tackle this project.

Thanks for the tips, Kris. Not quite a ten minute job for me since my garage ceiling has gyproc on it, and so was too close to the ceiling to get the gear out. I had to drop the unit by taking out the two heavy bolts holding it to the ceiling brackets, then rest it on top of a step ladder. It was quite heavy, so you want to be sure you have your ladder positioned to lay it on as soon as you get the bolts out. The tip on getting that little pin out were great. Thanks for the video. Very useful!

Great video! A guy who worked on garage doors for a living told me it would be a waste of time to fix this as something else would soon go wrong. I did it anyway. It works great. Had to use a 5/16 wrench to remove and replace one of the 3 screws that hold the assembly to the chassis on the top due to a peculiarity of my model. Hardest part for me was getting the chain back in place and then adjusting the operation of the door. The instructions that came with the parts kit were of very little help. Thank You very much for posting this great video! My wife will dislike me a little less now!

i just saved myself a buttload of money, and completed this repair thx to your video!!! Much appreciated!!!!

I bought the whole entire assembly kit off Amazon for less than $20. Thanks for this video brother.

thank you. I just had mine replaced today while watching your instruction every steps. taking out the pin from big gear was quite challenging. thank you so much. you helped me save some money. i don’t have to buy new one.

Kris. Thanks a bunch for the "great" instructions... much appreciated!!! To remove the gear, probably the easiest way to get the roll pin out is with a "pin punch" tool. The size you'll want is 3/16" or 4.8mm. You can buy one for $4 to $5 at a decent hardware or auto store. If you have a mechanic friend they'll likely have what you need. I'd steer clear of a center punch for it tends to spread the roll pen. Hope that helps!

Finished the replacement procedure this weekend. As noted here, it's a straight forward job. My replacement part pkg. came with the gear and sprocket assembly altogether already, so I simply replaced the entire piece, which made the job even easier! 2 of the 3 screws that fasten the top hat/chain sprocket to the unit are easy..........the 3rd one is tough to get at, and I couldn't get it back in once removed. I would have had to have removed some additional stuff. I left it out.

I was able to fix my garage door opener ! I bought the gear separate from Amazon for 6.00! Thanks for the video. Super helpful. Couldn’t have done it without the video

Great video, more useful than the instructions. I ran into a few things that others may be interested in knowing. First, clean the worm gear on the motor shaft. I used a small blade screwdriver and spun the shaft to get the gunk out. Then a paper towel with cleaner. Second, the door was down but the opener thought it was open and tried to close it. Fixed that by spinning the center screw on the limit switch to the other end. Only needed the gear, would have saved money not buying the kit.

Thanks Kris! Saved me a good chunk of change there! Took me about an hour and a half. Getting all the tools, getting the air compressor out and put together, etc... Tough to get that pin out w/o a proper size hole punch. Ended up finding an 8 or 10 penny nail and took off the tip. Also had to loosen and take off the chain to pull the whole rod unit on and off again, then re-tighten. What I didn't do was put it back on the right way as the little chain cover holes were not lined up. Oh well... not taking that apart again just for that! :o) Thanks again!!

I watched your video, ordered the part, and fixed my garage door opener. Thanks!

SOOOOOOO helpful. This video made something daunting super doable. Both of my garage door openers stopped working within a day of each other. With this video and the parts, I fixed them both. With the learning curve the first one took longer, but I was able to do the second one in half the time. Thanks Kris!

Worked for me on Sears craftsman 139.18846. Used replacement gear and sprocket kit part 41c42220a ordered through Amazon. Thanks for your post! Gave me the heads up on the problem with the opener and how-to repair.

Great video, and it shows exactly what happened to my garage opener. I live in Miami, FL, and the the reason why the gears were totally stripped is because we had a cold front (50's lol) and I learned that the sensors malfunction under this circumstances, so you need to press and hold the wall-mounted button in order to close the garage. All this going up/down takes its toll. We are back in the 70's and 80's so I hope this will work fine until our next cold front.

Thank you! This was exactly what I needed. My garage door opener looked just like yours on the inside with all the plastic dust. The worm gear was fine, only the drive gear needed replacing. $6 shipped on eBay with grease included. Can't beat that!

Kris, very informative video, just what I needed. A few comments that I would like to pass along. 1) Be sure to clean out the old dust and shavings as the first step after the body cover is removed, this will keep the dust and shavings from getting into the newly greased gears. 2) If you mark the top sprocket and chain so that when you reinstall the top sprocket and chain the marks line up again, this should eliminate the need to adjust the limits. 3) Be sure to apply grease to all the gears while the cover is off. This simple preventive maintenance will extend the overall life of all the gears, which in turn will allow your opener to have an even longer life. Again, thanks for this video, it was really very helpful.

Your "up and down stroke was off for some unknown reason", as stated at 8:48, was related to the small gear replacement at ~ 8:30. That is its purpose as shown by the long plastic screws adjacent to it. Pay attention to the position of the small gears when removing will avoid having to reset positions. Excellent video for the DIY'er. Only adding to it, you did a much better job explaining than i would have. :)

Kris, I'm a guy with 5 thumbs on each hand. Watched you video and I was able to repair the door opener. Thanks for taking the time to post your helpful video!!

it worked! save me i am not a handy person, but followed the video and each step, quite smooth process. it took me one hour as i move cautiously to make sure thing are done as instructed. Owe Kris a beer!

Just watched your video and it was a great help, just saved me money calling a repair service to come out and fix it, thank again.

Thanks for the video... I couldn't find the parts but was using the numbers on the back of my opener. The model number was for the logic board only, the model number of the entire opener was hidden by the light.

Thanks so much Kris!!!! Great video enabled me to fix my garage door opener. You rock.

Thanks Kris. After being quoted $120(the part costing "$35") i decided to order 2 gears (for $12) and watch your video.....

Kris, thanks for doing this. It made this job go a lot easier and I saved myself hundreds of dollars in buying a new garage door opener. I think I spent a total of 45 minutes on this repair, as I also adjusted the chain and the limit switches while I was at it. Thanks again!

You the man... 15 minute job? I pushed 2.5 hours !! HA! What a pain getting those 3 screws off & ESPECIALLY on. Not easy to get the gear back into place when you have the chain tension. Taking out that set screw took some serious time. I also had to adjust the travel & downforce for a good 30 minutes until things worked right. Thanks boss

I really appreciate this video you took the time to share.My problem with Liftmaster 1240 was the same as yours,stripped plastic drive gear.I am almost home free, waiting on parts to arrive.Capacitor did not look bulged or oily.

Thank you for posting this video. After watching your tutorial I was able to assess the problem, order the correct parts from Sears online, and it took me ALL day to actually take the gear out because I had a real issue getting the hex bolts off in the tiny space inside the apparatus. I made the mistake of loosening the two easier to reach nuts first and then the harder one was even more difficult to remove due to the pressure of the chain. I ended up using a 1/2 wrench to loosen up the chain prior to removing the shaft so that I could get that last hex bolt out. The tiny pin that was holding the gear onto the shaft was nearly impossible to remove and put back in again. I ended up using clamps and then a nail driver with a hammer to get that pin back in without damaging the gear. I finally put it back together and the mechanism is working but I made another mistake when loosened the chain, the door catch moved away from the engine and now the door goes back down and then up a bit but then is stuck. Tomorrow I will loosen up the chain again, take it off the spoke and move that door catch over. Please excuse my lack of proper names for tools and instruments. I’m a chemist, rather than a mechanic, but you made this look so easy that I had to try and I’m really glad I did! Thank you again for posting this.

Great instructions. Took a bit longer than your estimate but definitely easier than installing a new opener. And cost about $170 less! The opener works great and is incredibly quiet! Thanks!

I appreciate you & the fact that you explained everything in a manner that was easy to comprehend & understand. A great job all the way around!

Excellent video. You saved me from buying two new garage door openers. The only other suggestion I would have is to loosen the tension on the chain, at the tension bolt. This took a lot of tension off the slider unit and it was much easier to remove. Thank you very much!

Thanks Kris! The assembly was a little tough to manage out but after that it was all gravy. Reinstalled and adjusted with a few other videos.

Thanks Kris, this video made short work replacing the drive gear. I ordered the part (gear) on ebay for $5. U ROCK!!!

Thank you so much for this video. Very very helpful. I am not handy by any means but I found this video hoping this might shed some light on what was going on with my door. VOILA! Ordered the part from Sears, they had it in stock, I brought it home and swapped it out. Whole process took over an hour. Awesome video! Thank you for saving me a lot of money.

Truly helpful. Thank you. I anticipate that getting the 3 screws at the top will be difficult, but I shall overcome.

Great video! Followed your instructions to the "T" and the opener works like a dream. Thank You!