**WhItE-aNgEl**

Yeah I have this weird noise on my clutch pedal when I press it down it's like it's to tight or somethinh. It's kinda like a squeaky noise when I engage the clutch . I might take it to Acura this weekend

**WhItE-aNgEl**

Just corrected it sorry

94eg!

That is pretty common. They will want to replace the master-cylinder.

94eg!

You got it. As I said before, rev-matching takes the wear off the clutch. Double-clutching takes the wear of the synchros. Do both at the same time and you will never wear out either one.

BTW: I find it's a little easier to explain a rev-matching double-clutch process if you just use the term "clutch" to describe the physical act of both pushing in and releasing the clutch pedal. IE: "Clutch into neutral" or "Clutch from Neutral to 1st" or "clutch from 1st to 2nd". This better describes how the multiple actions are executed as 1 simultaneous step:

- Clutch into neutral
- Blip the throttle
- Clutch into lower gear

**WhItE-aNgEl**

Is the clutch master cylinder a wear and tear part? I'm still under warranty so if it's covered I'll take it this weekend

94eg!

Yeah sort of. They can fail at pretty much any time. The sound/feeling is caused by a spring inside the cylinder rubbing on the housing. It's not really broken, but it shouldn't really do that. Have a look through the TSB section. I think they posted one for the TL recently if I'm not mistaken. Print that out and bring it in with you.

My 03 Element had this bad. It would only get really creaky when it rained though (a rare event in Las Vegas). The dealer tried greasing everything, but replacing the MC was the only thing that made it go away. Later Honda issued a TSB for the Element and the 7th generation Civic.

**WhItE-aNgEl**

Just searched for it and no luck if there's a TSB please someone give me the link to it thanks

94eg!

Well I can't get the pdfs to open again, but it's the second to last one at the very bottom of the page:

TSB 11-004: (2004-2008 TL 6MT) Clutch Pedal Pops, Squeaks, or Clicks

https://acurazine.com/forums/3g-tl-2004-2008-93/3g-tl-technical-service-bulletins-tsbs-3g-garage-j-016-a-613659/

**WhItE-aNgEl**

i have one more quesstion what happens if you over rev when trying to rev match? and what are the risk of over revving when trying to rev match. thanks

ez12a

there's no real risk of "over revving" in terms of damaging the engine. Rev limiter still applies. A blip of throttle is a momentary stab at it. You're not flooring it for an extended period of time.

In terms of over revving as in revving higher than necessary to achieve a smooth shift, that's just something you'll need to practice and get a hang of.

It's better to catch the RPMs dropping from above the desired rpm than to force the engine to spin up if you dont rev match at all.

SouthernBoy

You wrote:

Double clutching :

1. Release gas pedal
2. Engage clutch
3. Put in neutral
4. Release clutch
5. Blip gas pedal
6. Engage clutch
7. Go to lower gear

Rev matching:

1. Engage clutch
2.blip gas pedal
3. Go to lower gear
4. Release clutch


In your Double clutching steps 2 and 7, you are not engaging the clutch. You want to disengage it. I know that is probably what you meant, but we need to be on the same page with this. Same error in Rev matching step 1.

Also in Double clutching step 3, you say Put in neutral. You're not really putting the transmission in neutral.. your pausing there on the way to your chosen lower gear into which you are downshifting.

Rev matching is not the same thing as double clutching in that it lacks two steps which you must perform when double clutching. As has been mentioned, rev matching will reduce clutch component wear and if done right, this wear reduction is very significant. But it does not reduce synchronizer wear. Double clutching does both.


Double Clutching:

• Remove foot from throttle.
• Disengage the clutch (fully depress the clutch pedal).
• Begin your shift to the selected lower gear.
• As you enter the neutral gate, pause and blip the throttle while simultaneously engaging the clutch (let the clutch out some or all).
• Disengage the clutch again.
• Complete the shift into the lower gear.
• Release the clutch.

Rev Matching:

• Remove foot from throttle.
• Disengage the clutch (fully depress the clutch pedal).
• Begin your shift to the selected lower gear and blip the throttle during the shift while the clutch is disengaged.
• Complete the shift into the lower gear.
• Release the clutch.

The difference between double clutching and rev matching is when you double clutch, you engage (release) the clutch when you perform the throttle blip.

Now as to how much to blip the throttle, you are going to have to watch your tach a lot until you get the hang of it and even then, you will still use your tach at times. I know I do. So way you're traveling along in fourth gear with the engine turning 2500 RPM and you see coming up a situation where you want to downshift. The difference in the ratio spread between fourth and third gears is roughly 75% (actually 73.5% but 75% is close enough). What this means is that in order to get a smooth downshift with your double clutch or rev matching, you are going to have to raise the engine speed up to approximately 3500 RPM in order for it to "catch" the wheel speed when your clutch comes out after the shift (I say 3500 RPM because after the blip, engine speed is going to fall).

AMUA6

iTrader: (7)

Lot's of good info in here! Kudos

GivatiTL

How many miles did you have on the original clutch ?

**WhItE-aNgEl**

80,000 when it started sleeping

94eg!

Well, when downshifting there is a very real danger of over-reving. Not just the engine, but the clutch disc itself can come appart if you have a royal screw up. Here is how...

http://www.teammfactory.com/gearcalc...=0&trannytype=

Open the above gear chart and have a look at it. You can see each gear can only support a vehicle speed so high. Imagine your traveling at 80mph in 6th (2600rpm) and you want to downshift to pass someone. Your target is 4th gear, but you accidentally put the stick into second. Now looking at the chart, you can see 2nd gear is only good to about 62mph. The instant you try to force the shift lever into second (yes with your foot all the way down on the clutch), the second gear synchro will accelerate the clutch disc to 8500rpm to match the speed of the secondary shaft. If this rpm is higher than what the clutch disc is rated for, the organic friction material could burst and fly apart (centrifugal force). And this will happen before you even try to let the clutch pedal out.

Now if the clutch disc manages to hold together, the next thing to happen would be you letting out the clutch (cause you still think your in 4th). Once you do, the engine will be accelerated to 8500rpm. Your motor's valve train isn't properly equipped to handle this high speed and you run the very real risk of floating a valve which "can" cause catastrophic engine failure (like piston hitting etc).

But this all is a real risk when downshifting no matter how you drive. It's also a very real risk when upshifting. Imagine going from the top of 3rd gear, and accidentally jamming it into 2nd. That's taking the clutch from 7k rpm to about 11,200. This is how you explode a clutch disc. My friend accidentally did this when speed-shifting his brothers near-new 07 Sti. The clutch exploded and they were dead on the highway.

He was pissed!!!

ez12a

^ ah yes the infamous money $hift. Seen a few members on the E46 fanatics forum do that. The transmission in that car can shift enough under load for someone to do that I guess, combined with the vauge shifter. TL owners should learn to appreciate the clearly defined gates of the 6MT. I love it.

call me a scaredy cat but one of the reasons why i never really go to the absolute red line in my TL.

**WhItE-aNgEl**

I tried doing this and it did not work.

**WhItE-aNgEl**

Wow! I did not know that. Shit now I'm going to be paranoid as F*** when shifting lol

SouthernBoy

Trust me, he's right (943g's post #55).

Just be careful. Anyway if you were to miss a shift on a downshift as he described when instead of going into 4th from 6th, you hit 2nd by mistake, you would know it as soon as you tried complete the shift into second gear due to the resistance the synchronizers would produce. And if you get it into 2nd, as soon as you attempted to re-engage your clutch you'd notice your engine fighting your attempt because it would be turning nowhere close to the RPM range it would need to be in.

jeeva86

Is this true? Engine will hold at 3.7?? For how long?

SouthernBoy

Approximately less that two seconds. I would not rely upon this because doing so will prevent you from learning the proper technique of double clutching downshifts. Then if you buy another car with a manual or drive someone else's, you'll have trouble using these techniques. Much better to do it correctly from the start and not rely on the car to do some of the work for you.

94eg!

I had a chance to mess around with this a few times last night and I can say it's really neat......when it does work. I noticed the ECU wouldn't hold the rpm until you move the shift lever into the intended gear (before letting the clutch out). Once it's in gear, I actually witnessed the ECU push the rpms back up from being too low, and not just hold them as rpm falls. It's pretty fancy, but doesn't have much practical use on the streets (where traffic dictates driving style). I am so used to rev-matching & double clutching that I have hard time training myself to slow down and really pay attention to exactly what the Drive-By-Wire is doing.

It is pretty cool when you see it though, because you let out the clutch so ridiculously long after blipping the throttle, but it's just phenomenally smooth. I imagine most of the time it's just seamless and goes unnoticed as you repeatedly execute seemingly perfect heel-toe downshifts.....tricking you into thinking your Michael Schumacher or something.

Thanks Honda America.

anthracite_ftw

Are you familiar with Nissan's "syncro rev match" feature on the 370z? I haven't driven one, but I've watched videos and it looks pretty neat. Seems like an even more idiot-proof system than what our TL's have. Without even touching the gas, you can slot the shifter into any lower gear, and it will rev straight up to the correct RPM. Step right off the clutch, and there shouldn't be the least bit of shock through the drivetrain.

While I think it's a really clever feature, I'm still in your boat. When it comes to driving every day, I expect I would turn it off. Something about double-clutching, giving the gas pedal a good whack, and then releasing the clutch as engine speed falls to the appropriate rpm, just brings me immense satisfaction. If operating the 370 manual tranny requires very little concentration and/or risk of screwing up, you might as well buy an automatic?

gilla_monster

iTrader: (2)

I think I need to study a transmission diagram or watch a video to see what is actually happening in the shifting process. I never truly appreciated the concept of double clutching because I thought it was redundant since I was already rev-matching. Now I discover that my sychros are freaking out every time I blip the throttle on my way to a lower gear. My only complaint is that I feel like it would take too long to perform all of these steps without loosing "the perfect downshift". I guess I need to practice...

94eg!

With the crazy heavy flywheel on this car, you have plenty of time to execute a double-clutch shift. There are really only 3 steps that you separately execute in your brain.

- Clutch into neutral
- Blip the throttle
- Clutch into gear

It's really that simple. Of course when I say the word "clutch" I mean press-and-release the pedal. But this makes it easy. Once you practice it you will get very comfortable in no time if you already are good at rev-matching.

As for the mechanics of it, here is a decent video I found really quickly. Not our gearbox, but it gives you a good visual reference. This is a 5-seed transaxle:


This video illustrates a RWD gearbox (which is quite different), but I like the detail about how the synchronizes work. That's not explained in the transaxle video above.

SouthernBoy

Excellent find and post 94eg!!

Folks, study these videos well and ask questions. You will note several things in them. 1) When you shift gears, you are not actually shifting gears at all but rather sliding a hub into a collar on a given gear to transfer engine power through that gear. 1) You can clearly see in the second video how the hub-and-collar interaction takes place.

It would have been nice if a little more information and display had been done regarding the synchronizers but you should get the picture. Think of them as little clutches which have the job of equalizing gear and shaft speeds before allowing hub insertion (i.e. shift completion) to take place.

Also note the reverse gear. In these videos, those gears do not use the hub and collar arrangement. They use slider gears. This is the reason you hear people "grinding their gears" when trying to go into reverse. It is also the reason why I have written previously that you should first shift into a forward gear before shifting into reverse. Now our TL's have a synchronized reverse gear so this is not necessary... but I still do it myself.

Also note that all of the forward gears are in mesh all of the time. That is why manual transmissions like this are referred to as "constant mesh" transmissions.

Again, thanks to 94eg and great post my friend. I'm certain you've helped a lot of folks with this.

SouthernBoy

Now a word about double clutching.

After you have watched these videos, you should have a pretty good understanding of what's going on in our transmissions when we are operating our cars. To complete the picture, now you must add in the clutching component to really understand it all.

As was shown, the friction disk is attached to the transmission input shaft. The flywheel is bolted to the rear of the crankshaft and the pressure plate is bolted to the flywheel. When you depress the clutch pedal, you are forcing the pressure plate to release its applied pressure to the friction disk AND the flywheel (the friction disk is sandwiched between these two components). Releasing the clutch pedal re-establishes this applied pressure.

When you begin a downshift, you remove your foot from the throttle while at the same time depressing the clutch. With this interruption of power from the engine to the friction disk, the transmission input shaft, and the gears riding on it, begin to slow down but the output shaft still continues to turn since it feeds the drive wheels. If you do not double clutch, your synchronizers have to pull the speed of the selected gear and the input shaft up the that of the output shaft via that gear. This causes wear on the synchronizers. Granted this is what they were designed to do, but you will shorten their life by downshifting without double clutching. And with the problems we've seen with our TL synchronizers (third gear in particular), why not practice a technique that will postpone any undue wear?

94eg!

Thanks for the kind words.

I just wanted to add that when you depress the clutch and move the shifter to neutral, the rpm of the main-shaft drops a lot slower than the rpm of the engine. This is why Transmissions can grind if you skip a gear on an upshift from high rpm. Say your at top of 3rd (7k rpm) and you want to quiet things down and skip straight to 5th... It's very easy to for the synchro sleeve to blow right past the syncrho before it can slow the mainshaft to a decent matching speed. If this happens, you will get a grind. This is why skip-shifting is bad. Better to quickly go to 4th then 5th to spread out the work of slowing the mainshaft onto both syncrhos. Skip-shift grinds are more typical on high rpm motors like the S2000 or Integra VTEC, but it's always bad for any transmission.

The important part to remember is that when it comes to synchronizers, it's all about rpm. The greater the rpm difference between two gears, the harder the synchro has to work. If your doing lots of high rpm shifting, then double clutching and rev-matching is a must. If just drive like a normal person and keeping it under 3k, then it's not as critical..... But it sure is fun, and your trans will last longer.

SouthernBoy

Good points. I skip shift upshifts on rare occasions but I know what to do to not induce any undue wear on my synchronizers. I wait a little long for engine speed to drop to where it needs to be (this is why we have tachs), and then I complete the shift.

From time to time, I get some static from people on this website about my position on double clutching downshifts but I stand by my position for the simple reason that facts are on my side. Do we need to... have to double clutch, or even rev-match, a downshift? Of course not. But doing this will result in a huge extension in the life of clutch components and synchronizers. So it is really down to that. Now from a personal standpoint, I must admit I like doing something that is advantageous to my car and that very few people who drive manual vehicles do. Call it a little personal satisfaction.

94eg!

You can also double clutch during your skip shifting and you won't have to worry about a delay or wear. Double clutching an up-shift is really awkward the first time you try it... lol

SouthernBoy

One would only do this is engine speed has dropped below where it needs to be for the skipped higher gear (say a 3rd to 5th skipped shift). Otherwise, engine speed will drop to where it needs to be for 5th on its own. If you allow it to go lower than that (and of course the car is slowing down while this is taking place) then yes, double clutching will bring things back into line.

But since I rarely skip shift, this is something I don't worry about.

TL ROOKIE

Good Info

94eg!

I don't think were talking about the same thing.

Double clutching an upshift does not involve rev-matching or even touching the throttle. It's just meant to bring mainshaft speed down WITH the engine speed as the revs fall. Completely unnecessary with a regular upshift.

But because main-shaft speed does not drop as quickly as engine speed when you press in the clutch, you could use a quick double clutch action in Neutral to slow it enough for a safe 3rd-to-5th skip-shift without imparting that extra duty onto the 5th gear synchro.

Yes your correct about re-rev-matching, should your rpms fall too far during a shift...

SouthernBoy

Ok, yes... I see now what your meaning was. Thanks for the added info.

gilla_monster

iTrader: (2)

All this has been very informative! For those who learn visually, here is another video that helped me understand the actual design ofthe synchroizers and how they work.

ohsixMTee

iTrader: (2)

Interesting information in here. I've read through and began to modify my driving habits. I've always driven conservatively but so far my shifts are noticeably smoother and my average MPG is higher than I've seen it since my ownership.

I've always rested in neutral at lights, etc. with my foot off the clutch but wasn't downshifting the ideal way.

I'd downshift and RPMs would jump to ~3000 which I just thought was how it's done.......now I let the engine brake the car in gear until roughly 1500 or so and it makes transitioning into the next lower gear so much smoother. Obviously it feels a lot better for the motor/clutch/trans as well.

Thanks for all the information!

anthracite_ftw

My technical knowledge of this is limited, but you just cleared up something I'd been wondering for a long time. My second gear synchro is kind of weak, thanks to the previous owner. Third gear synchronizer was replaced 6k miles before I bought the car, so that's not really an issue.

When it's cold though, or I have to complete a higher RPM 1-2 upshift, 2nd gear will require a little more effort, or even grind sometimes.

I've noticed it goes more smoothly if I double clutch (no rev-match) as I'm passing through neutral. Either way (single or double clutch), I wait until the engine is at the appropriate speed before putting the shifter into 2nd. I had suspected the mainshaft might not be decelerating at the same rate as the engine, and engaging the clutch was giving it a little help.

It's just kind of sad that I need to do this even if I'm not skipping gears. I love hondas, especially manual ones, but I don't know if I'd ever buy one used again.

ez12a

2nd is also a little hard for me if the transmission's cold (the engine warms up faster than the trans. After the engine completes warm up, after a few more minutes the trans becomes a lot smoother for 2nd and 6th. I cant really get into 6th at all when it's cold unless i double clutch it.

it's "crunchy" or i feel some kind of gear resistance. It's not an outright grind. I usually shift way early though (below 2k) in the morning rather than do a higher rpm shift.

running GM FM fluid.

edit: it seems to be an ongoing "problem" with cold transmissions (4G TL): https://acurazine.com/forums/4g-tl-problems-fixes-297/hard-shift-1st-2nd-841992/. Just drive slow and shift early while the trans is cold. I usually cruise in 5th going 45-50 to speed the process.

94eg!

That is a great video posted above. I know Honda is making double & tripple synchro gear now though, so it may be a little more complicated that was shown. Probably just more layers of brass rings for the sleeve to slide past. This is also most likely the reason we feel this occasional notchyness. I suspect it's the feel of the sleeve sliding over and banging into more than one of set of chamfered teeth.

As for the comments on temperature....You can bet that it plays a part in the performance of the fluid and synchro material. Same way a clutch starts slipping if it gets too hot. I'm wondering if anthracite_ftw has had a chance to try the GM/AC Delco FM fluid. It's thought to give the syncrhos a bit better bite and allow them to do a better job even if they're slightly worn.

It eliminated an awful 3rd gear grind we had in our 03 Element AWD. A poorly executed dealer synchro replacment left our truck with questionable shifting quality. Never had a single crunch-shift or pop-out again after I put in the GM fluid.

94eg!

In this pic you can see how the 3rd-4th gear synchro set (#3) on the mainshaft has a lot more rings than the 5th-6th syncrho set (#7) having what looks like three friction surfaces for each gear instead of one. The 5th-6th set is pretty much the same as what we saw in that video except those little keys are integrated into the brass ring instead of being a separate piece. I wonder if this mulit-ring setup is the the source of all the notchyness Honda has with it's 6-speed transmissions.



You can also see how the 1st-2nd syncrho set on the countershaft has many synchro rings as well. I wonder why people don't have as many issues with this one? My guess is because probably do a lot less bad-habbit downshifting into these two gears. Who knows.