What happens when I grind my gears?

Everyone who drives a manual transmission car has ground the gears at least once, usually followed by "ouch" or "sorry".
I'll show you how the synchronizers work and what parts grind together.

[@joshsnyyper]

I’ve always wondered the kind of damage I inflicted while learning to drive manual 😂

[@makenziechild4056]

who came here after crunching a gear?

[@jtandrews3]

Judging by the comments, I'd say a lot of them did.

[@mashedpotatoes5323]

I accidentally grinded second until it went into gear, how many times can you do that?

[@J_N969]

@@mashedpotatoes5323twice

[@zrgaming9392]

awesome video John. Thanks for sharing your knowledge

[@EFRANEED]

Thanks a lot for the video, makes me understand what happens when this kind of grind has happened to me

[@DGQ1Q2]

Thanks Jhon for the video and the answers in the comments section. Very usefull..and accurated.

[@hirenmodi4393]

It was very informative. Thanks John

[@thestorminmormin1442]

Everytime he says synchronizer, take a shot.

[@ovo_indigo]

accidentally grinded my gears in the exact way you described in the scenario at the start of the video and when it happened i damn near had to get new underwear since i thought my trans was blown (which i understand is a ridiculous thing to think but at the time i was just so shocked at what happened lol) but im glad to know now that if the grinding isnt prolonged (which wasnt the case for me since i stepped on the clutch pedal again as soon as i felt the shift knob go crazy in my hand) and it isnt done often then the gears should still be fine.

[@dodge25]

I just grinded my reverse gear 🥲

[@Kevin_C97]

@@dodge25 Same, I was still slightly moving forward and went to throw it in reverse and heard that dreaded noise, clutched in the second I heard it. Never a good feeling.

[@monsesh1316]

​@@Kevin_C97​ I saw a guy "experimenting" with this. He accelerated to a decent speed then immediately shift to reverse while he's still in motion. It's on KZbin.

[@epicdata_3D]

I accidentally grinded three times in newly purchased car😢

[@speck213]

Had a random question, found an answer. Thanks for the vid!

[@sorinal1234]

Excellent ! More !!!!!

[@MrSajigsnair]

Hi John . Thanks for this informative video, It really helps one understand the technical aspects of the transmission. By the way, recently I forgot to depress the clutch and shifted into a gear while my brand new car was stationary. This caused the instant grinding noise. Would you please let me know if my car's transmission / engine will continue to perform without an issue for the rest of its life , taking into consideration that such accidental yet occasional grinds could still happen to my car's manual transmission in the future ?. Thanks !

[@edijszuimacs6832]

When he said you heard this noise before I straight away had to say defooooooo that noise I don’t like it 😹 gets me scared

[@shift2rockz858]

Hey, thanks for the mechanical insight and what takes place during a grind. I'm relatively new to driving Manual transmission vehicles and just had a similar scenario unfold as you demonstrated at the start of this video. However, as I got out of the vehicle, there was a relatively strong odour emitting from somewhere, which I brushed off as being the clutch following the grind and it was gone when j returned a few minutes later But when I drove the vehicle again, shifting normally and all, and came to a stop and got out the same odour lingered in the air. Is this normal and will it go away after a few drives, or do I have something to worry about? The vehicle is behaving normally as in no grinding or abnormal noises. Thanks

[@Zloner]

Nice video! I had quite a bit of grinding due to a bad cable. Cable was replaced but every now and then the gears seem to engage in a "stepwise" fashion. Meaning instead of a direct and single "sharp" engagement I get several very short sharp engagements. Are these my synchronizing rings saying goodbye?

[@jtandrews3]

The synchronizer sleeve has to slide over the ring first, then the gear, so you'll often be able to feel two clicks as it goes into gear. This is normal.

[@ojmacek]

Hey man, awesome video. Happened to me yesterday for the first time in 2 years of driving stick, 5k rpm, 1st to second... Should I be worried? I lasted like half a second and i didn't force it in, it was kinda light..

[@evanmull8539]

I have a 2020 with less than 15k miles on it and sometimes when going from 3rd down to second if I don’t properly rev match I grind the gear…. I also like double clutching when I down shift and sometimes out of old habits I’m engaging second in the middle Of double clutching 😖😖

[@igorholizna3321]

It happend to me once .Can i cause any damage to gearbox?

[@braydenmann3360]

My 2000 mustang gt will go into every single gear just fine and then going into 5th gear it grinds and I can’t get it into 5th cause it just grinds 😭 no idea what to do….never dropped a transmission, nothing like that….so what do i do? Not use 5th? That’s what I’ve been doing

[@calebhouweling760]

I have a question... Does the Synchroniser come into play when changing gears or when the clutch pedal is released? just a lil confused

[@jtandrews3]

The synchronizers work any time you move the shifter into a gear. They also try to work even if the clutch pedal isn't pressed, which is why shifting without the clutch is so hard on the synchronizers.

[@calebhouweling760]

@@jtandrews3 so it is in the action of moving the gear knob then. Not the clutch release

[@jtandrews3]

Correct. The circular synchronizer spring inside the synchronizer sleeve pushes on the three little rectangular synchronizer keys. So when you push into a gear, the keys push the synchronizer ring onto the cone part of the gear. That's so that the synchronizer ring doesn't just slip inside the synchronizer sleeve. Once the synchronizer ring starts to push on the gear, the spinning action will rotate the synchronizer ring so it's offset from the sleeve. Then once the speeds are synchronized, a little bounce-back makes the synchronizer ring slide into the sleeve and the sleeve can engage the gear.

[@charliesmith7942]

@@jtandrews3 how many low speed accidental grinds can you do before permanent damage? I drive a 6 speed 2018 honda civic

[@jtandrews3]

It depends on what you define as permanent damage. One grind can produce measurable damage, but not any noticeable functional difference. Usually it takes a lot of grinding gears before any noticeable functional damage occurs. This is one of those questions that needs an experiment to quantify an answer.

[@kk-yy8oi]

Thank you so much for the video, nicely explained...I have a question please, just happened last night .. I was at intersection I was on 2nd gear and the car was very slow that it almost fully stopped , after I checked that there are no car and my clutch was fully pressed, I didn't out in neutral and as I was trying to switch to 1st and while the shift was in the position between 1sr and 2nd..I felt the very light grind bit no sound at all . . May I ask why was that happened? And did I do any damage to it? It wasn't a grind like I had many years ago.. this time no sound at all but just felt a very slight grind for just 1 second and I quickly put back in neutral ... Thanks again

[@jtandrews3]

Although I cringe every time I grind my gears, it doesn't do significant damage. But to answer your question, let me see if I understand. You felt a grinding when the clutch was fully depressed. Yes, you can grind gears with the clutch fully depressed. This can happen when the wheel speed and the input shaft speed don't match for the gear you're trying to put it in and you go halfway into gear and back out part way and then try to put it back in gear. Normally, the synchronizer keys push the synchronizer ring against the gear until it turns it offset to the teeth. Then your synchronizer sleeve is pushing against the teeth of the synchro ring until the input shaft matches RPM. At that point, the input shaft & clutch bounce back and the synchro ring lines up as you push it into gear. But if you start to move the shifter back, the synchro keys no longer press against the synchro ring, allowing the synchro sleeve to go over the synchro ring and start to mesh with the gear that's spinning at a different speed. So basically, it was a very gentle gear grind. I hope this helps.

[@kk-yy8oi]

Thanks for your reply.. yes I fully depress the clutch and that's what we supposed to fully depress all the way till the dead end right? By doing that will there be a stop for the clutch peddel? Cuz I sometimes felt like the peddle is touching the ground or I'll make the clutch arm lose ...But I guess I worry too much😂😂

[@kk-yy8oi]

Fully depress is the word and that's supposed to be to all manual car and I was just worry if I put too much force and fully depress I might do some damage to the clutch pedal

[@kk-yy8oi]

But I guess all clutch pedal are designed to press all the way to floor

[@red666A]

Sometime it could be bad cylinder slave, master cylinder, air hydraulic system, low tranny fluid, can cause it grind and not into gear.

[@wrathofpaulii]

sometimes this happens to my Challenger when i'm stopped and i shift into reverse before I let the engine rev down first. I assume that it's OK for this to happen once in a while, but don't make a habit of it!

[@jtandrews3]

Correct. Some vehicles don't have synchronizers on reverse. In that case, you need to be fully stopped and put it in one of the forward gears before putting it in reverse. That will stop the clutch disk from spinning. Some cars have a form of a synchronizer that is like a brake ring. It stops the clutch disk, so you have to be stopped before putting it in reverse.

[@rremdog5000]

What’s it mean when the clutch is in and you go to shift and you feel the gears grind a little bit before even letting the clutch out?

[@jtandrews3]

If it happens most of the time you shift into that gear, it sounds like a worn-out synchronizer. But it is possible to grind gears on perfectly good synchronizers if you move the shifter back and forth going into gear.

[@Shadoom1989]

hope i didnt ruin mine it happens once and i was like “ohhh shiiiiit”

[@dilpuneetsingh]

I have accidentally done gear grinding two times when I shift to first gear since bought my new car. Is there any point of concern?

[@jtandrews3]

I wouldn't worry about it.

[@bradensmith888]

Why does depressing the clutch pedal result in a no-grind situation, but failure to depress the clutch (even at low engine rpm) results in a grind? The synchronizers should be doing their job regardless of clutch status, right? For example, in a 3-4 shift with the clutch depressed, the car wheels are still turning, so the gears in the trans are still turning. The input shaft and gear sets are turning at different rpms, so the synchro has to get the gear set caught up to speed. Why is this different when the clutch is not depressed to shift?

[@jtandrews3]

Right where you said " . . . so the synchro has to get the gear set caught up to speed.", remember that the thing that gets caught up to speed is the input shaft. If the clutch pedal isn't pressed down, then it's not just the input shaft, but the entire engine also. If you try to shift without the clutch, it won't go in gear if the synchros are in good shape. If it just grinds into gear, then the synchros are already worn out. If you're able to rev-match the engine, the gear may slide in when the RPMs match. But that's wearing on the synchros. So since it's faster to shift with the clutch, the only time you'd need to shift without the clutch is when there's a problem that makes it so you can't release the clutch like a broken cable, or hydraulic clutch problem. And then you limp it home or to the garage for repair.

[@JayIand]

I just bought a 350z manual and sometimes when I downshift I try to rev match but my shifter doesn’t go into go into gear do yk why? It’s almost like the trans and the shifter isn’t lined up like a block when shifting into the gear

[@sethjansson5652]

Either it's a "notchy" shifter or the syncromesh isn't matched in revolutions to the gear you're wanting to go into. The best thing to do is to double clutch with two rev matches.

[@JayIand]

@@sethjansson5652 thank you I realized 1 gear down shifting from 2nd needs to be at least 2k but I’ll look up what notchy shifter is just to be sure

[@sethjansson5652]

@@JayIand It just means that shifting isn't as fluid as you'd like, as in you have to be pretty precise with the shifter.

[@zypher5876]

Hi, I have a similar issues however mine occurs when I downsfit. I'm in 3rd and comming to a stop so I press the cluth and shift and it grinds even if my foot is still on the cluth. I rev match as well, but it should not matter cause I don't release the clutch anyway. Does anyone know what the problem might be ? My car has 140000km or 87k miles and is about 5 years old

[@jtandrews3]

It sounds like the synchronizer is worn out. When the clutch pedal is pressed down, rev matching doesn't work since the clutch disk is disconnected from the engine. You can double clutch and rev match with the pedal up before pressing it down and then shifting into gear. Rev match a little high to allow for drag to slow down the clutch disk during the time it takes to put it in gear.

[@food-jitsu955]

Recently, I was trying to get in reverse gear, lifted the clutch very slowly, car didn't move and I hear that same whining sound, at which I realized that I just put the gear halfway and not all the way in reverse. My question is, does that do any particular damage? Cheers for the information, awesome vid!

[@jtandrews3]

Just minimal wear. If reverse is synchronized, it's often just a brake ring that stops the input shaft. In those types of transmissions, you need to make sure the car comes to a complete stop before trying to put it in reverse. Otherwise, it'll probably not go in, or grind going in. If reverse doesn't have a synchronizer, then you'll notice that you need to put it in another gear before going into reverse, otherwise it grinds every time. If someone grinds the gears enough, the synchronizer sleeve and gear can get enough damage to start popping out of gear, or no longer be able to engage that gear. Usually that type of damage occurs after the synchronizer is worn out and it always grinds going into that gear.

[@food-jitsu955]

@@jtandrews3 noted, and thank you!

[@mMI350]

Hello. Today I heard the grinding noise for the first time when changing gears. I was in 4th gear and when I tried to shift to fifth I heard that sound and I was honestly scared. It was my mistake because I didn't press the clutch enough when I wanted to shift into 5 as quickly as possible because I was overtaking. Now I'm wondering if I've potentially done some sort of damage

[@gavinclaassen6440]

My step mom had a seventies era VW golf, and we lived in a cold part of the world, especially in the morning, so after breakfast, we all get ready to go dressed up with sweaters etc, she would start with a choke start whilst in neutral and once running, she would adjust the mirrors and seat etc , the she would press her clutch and push the gear shifter over to the left and then push down on the shifter stick to go further as required in golfs to get reverse, then move it forward where reverse is on golfs, then proceed to look backwards to see where she was going to reverse to , as she started releasing her clutch the gearbox would let out a sound like a long wet fart , as I got older, I realized the gears were grinding, and it was her farting 😅

[@bethalpha]

I put in 3 clutch kits...... In 1 month.. Luk.... Makes a boat motor noise in between each gear The noise drive you crazy..... at bite point..... I imagine the clutch is burned up Buy now I don't think it's gonna last long....Chinah

[@arefinlabib4630]

so how many grinds at what RPM is GENUINELY bad for a manual transmission with a car around 200 hp?

[@jtandrews3]

Horsepower vs. grinding gears is virtually irrelevant. The two biggest factors are 1. how hard you're trying to push the stick into gear as it grinds, and 2. the RPM difference. When you do a transmission fluid change and see how much metal is stuck to the magnet drain plug, that gives you an indication of the damage. But usually people will wear out the synchronizer ring before the teeth. In other words, it will usually grind into gear before it no longer stays in gear. I doubt there is anyone who daily drives a manual transmission that hasn't ground the gears. Ecclesiastes 7:20.

[@arefinlabib4630]

@@jtandrews3 Awesome man! Thanks for the response. If you don't mind, there's one more thing that I have observed happening to a MT vehicle which is stiff shifting when going to first from second and the other thing is when the car is on, stationary, press the clutch in fully and shift to 1 quickly then there is a bit of mechanical resistance and a shake...but right after that (while clutched in) going back to neutral and to first again is silky smooth. Any idea on this? There are no mechanical lock out on the transmission I have and all the parts are dialed in correctly. However, keeping the clutch in for a while and doing shifting quickly resuls in a silky shift. Let me know ur thoughts on this. Thank you.

[@jtandrews3]

There are probably several things combined that make it hard to shift into first. 1. Cold weather making the gear oil thick. I've also noticed sometimes it's hard to get into first, especially when it's below freezing. 2. When you're stopped and the only thing turning in the transmission is the input shaft. 3. The synchronizer depends on a bounce-back to get into gear. If you don't get that bounce-back, the synchronizer teeth don't move back to align with the synchronizer sleeve so it slides into gear. This is what happens occasionally in cold weather when you're pushing it into first, but it just won't go in. Then when you shift into second and back into first, it changes the angle of the synchronizer sleeve slightly and it magically goes into first. You also mentioned a shake is when going into first gear quickly when stopped. That's because the synchronizer is grabbing the input shaft speed and quickly matching the gear (and clutch disk) speed to the same speed as the synchronizer sleeve, which is 0 RPM when stopped. Basically the clutch disk was spinning at engine RPM and was stopped by the synchronizer when you put it in first. Afterwards, when your clutch pedal is still down and you shift into neutral and back to first, it's smooth with no shake. On the second time, the clutch disk was already at 0 RPM, so the synchronizer didn't have to do any work to go into gear.

[@michaelxie4563]

@@jtandrews3Thank you for the video. I accidentally grind gears a few time. I wonder how many times the synchronizer can withstand the abuse

[@slimjim4773]

My vehicle does this everytime i go in 3rd, i have to rev match everytime.

[@DGQ1Q2]

I guess only downshifting right?

[@slimjim4773]

@@DGQ1Q2 I’ve only been driving clutch for about 4 months lol, newer clutch cars have auto rev match. So yeah, it’s not easy to “correctly downshift” when youve been doing it for only 4-5 months.

[@PinChE_LoCo]

☺️ oopsie

[@user-lf9kn4rg6p]

יש לי רעש של שחיקה כשנכנס לשלישי מה זה הגיר התקלקל או לא? תודה

[@jtandrews3]

זה נשמע כאילו טבעת הסינכרון בלויה. בסופו של דבר, ייתכן שהוא לא יישאר בהילוך 3 יותר.

[@crazynight1518]

I have a bad synchro in my 2nd, i double clutch and it does fine for the most part. I even most the time try to just take off in 2nd since my trucks geared so low