|WikiProject Automobiles||(Rated C-class, Mid-importance)|
|WikiProject Technology||(Rated C-class)|
|This is not a forum for general discussion about transmissions. Any such comments may be removed or refactored. Please limit discussion to improvement of this article. You may wish to ask factual questions about transmissions at the Reference desk, discuss relevant Wikipedia policy at the Village pump, or ask for help at the Help desk.|
- 1 Archives of past discussion
- 2 Starting when stalled due to water in engine
- 3 Moved a Benefit to a Drawback
- 4 Truck transmissions
- 5 Images
- 6 Gear change "Plate"
- 7 Porsche Servo Synchromesh
- 8 Synchro/non-synchro vs constant mesh transmissions
- 9 Crash gearbox
- 10 Lexus IS F
- 11 Contradiction?
- 12 One drawback is not a drawback, propose removed from there
- 13 "intuitive"
- 14 Benefits and Drawbacks Section
- 15 Illustrations at the end
- 16 Revised "complexity and learning curve."
- 17 Lots of clutch use in heavy traffic? Not true!
- 18 U.S. bias
Archives of past discussion
Starting when stalled due to water in engine
"This is useful when the vehicle will not start, but must be immediately moved e.g. off the road in the event of a breakdown, if the vehicle has stalled on a railway crossing, or in extreme off-roading cases such as an engine that has stalled in deep water."
Starting a car that has stalled because it sucked up water will break the engine. Water is incompressible and when a piston is in the compression stroke the water will prevent the piston from moving. However the starter engine has more then enough power to bend/break conrods and I can easily blow the piston out of the engine block —Preceding unsigned comment added by 126.96.36.199 (talk) 17:25, 1 February 2011 (UTC)
- If you manage to stall in water by, for example, drowning the ignition system then one can indeed winch the vehicle out on the starter. Do not ask me how I know this :-(. Mr Larrington (talk) 13:27, 4 July 2011 (UTC)
Moved a Benefit to a Drawback
This sentence "Manual transmissions place slightly more workload on the driver in heavy traffic situations..." was incorrectly placed under Benefits when it's clearly a drawback of manual transmissions. I've moved it to the right category. —Preceding unsigned comment added by 188.8.131.52 (talk) 10:48, 24 January 2010 (UTC)
In my humble opinion, this section contains too many weasel-worded statements like "most heavy-duty transmissions are non-synchromesh." How many is most, how many kW and Nm is heavy? Its point of view is also not neutral but biased towards Nort America. I cannot give any numbers but definately most lorry transmissions are either synchronised or automatic in Europe. Best Regards, Anonymous Reader, Jan 2013. — Preceding unsigned comment added by 184.108.40.206 (talk) 14:56, 18 January 2013 (UTC)
I talked to an old time truck driver in my travels about why truck transmissions do not have syncromeshes, he basically said given the sheer number of gears or gear combinations of a truck transmission, you could easily get lost in the shift pattern of that transmission and not having syncromeshes eliminates the possibility of putting the truck in the wrong gear and causing catistrophic damage to a very expensive motor or transmission. That and syncromesh transmissions were uncommon even in passenger cars until the late 1940s and by that time became the norm and standard for the trucking industry. Why add more parts that can wear out or fail to a drive train component that only takes a week to learn to shift without a syncromesh and is a skill good for a lifetime? Simple business economics. European trucks are different as they are typically smaller than their American counter parts, and therefore use a less complicated transmission for their industry. — Preceding unsigned comment added by Briansellman (talk • contribs) 13:40, 1 January 2012 (UTC)
I put a "fact" tag in the truck transmissions section after the paragraph about operating a truck transmission. While it is true that the proper technique for starting-off with a heavy truck is to completely release the clutch before using any throttle, it is not true that adding throttle won't help the truck move. Just try getting 75,000 pounds of truck started on a steep hill without using the throttle and you will see how much it helps. Rsduhamel (talk) 07:45, 2 November 2008 (UTC)
- Steep hills are an extreme case that do not disprove the statement, and if the load (on level ground) is particularly heavy or if the ground is soft, you'd use low gear. For a normal standing start you'd just let go of the clutch, which makes the statement completely correct. Why you think it's wrong because you handle an extreme case differently is beyond me. --220.127.116.11 (talk) 04:20, 1 April 2009 (UTC)
I drove a semi about 15 years ago that used a "box shift". It was similar to a standard "H" pattern, except that 3 and 4 (and thus 7 & 8) were in reversed positions, so that you traversed them as if you were outlining a box. 9th gear and reverse were up and to the left, where 5th is in most standard 5 speeds in modern cars. Unfortunately, could not find info on this with a cursory search, so perhaps I have the terminology wrong. Would love to see that included if someone can find this information. —Preceding unsigned comment added by 18.104.22.168 (talk) 06:04, 23 October 2009 (UTC)
The entire truck section seems to be heavily geared towards North American facts without mentioning this and without taking the rest of the world into account. The section states, "Some trucks have transmissions that look and behave like ordinary car transmissions - these transmissions are used on lighter trucks, typically have up to 6 gears, and usually have synchromesh." A bit later it says, "Multi-control transmissions are built in much higher power ratings, but rarely use synchromesh." Both statements are true for the North American truck market, but not necessarily elsewhere. As one can easily learn by checking out, say, Volvo Truck's UK web-site, their heaviest duty truck model (the FH 16 with up to 700 hp) can be ordered with a several variations of a 14-gear synchromesh transmission. Similar options exist for Volvo's other trucks. A sample spec sheet for an FH 16 truck can be found at http://datasheets.volvotrucks.com/getfile.aspx?id=1023756. This document leads to several transmission specs, one of which is http://productinfo.vtc.volvo.se/files/pdf/lo/VTO2814B_Eng_01_953764.pdf. The latter document has a section titled "Cable link and servo function for high driver comfort" that describes how the synchronization works. While it is also possible to order Volvo's trucks with automatic and automated transmissions, the one option they don't have on the international market trucks are unsynchronized manual transmissions. (I am using Volvo here as an example only, the same can be verified for MAN, DAF, Mercedes and other truck manufacturers.) — Preceding unsigned comment added by Mmayer (talk • contribs) 06:53, 20 December 2011 (UTC)
Sure could use some reasonable images of how it works, esp syncros, dogs, shift rails etc.
I agree! Although I know a fair amount about the topic, not every reader has a technical background. I had hoped for a better description of synchromesh, as well. Nikevich (talk) 07:13, 13 October 2011 (UTC)
Gear change "Plate"
|Non article-related talk|
|The following is discussion that is not related to the article and has been hidden per WP:NOTFORUM.|
Anyone have any idea what these 'http://www.dsvs.co.uk/images/gearstick.jpg' 'http://www.rosneathengineering.co.uk/images/gearstick.jpg' are called exactly? --22.214.171.124 (talk) 19:38, 17 May 2009 (UTC)
Porsche Servo Synchromesh
The Porsche synchro was not conical. Instead it used two small curved plates that acted much like a leading-shoe brake to bring the gear and sleeve to the same angular speed. I'll try to dig up an old manual I have and explain in more detail. I also agree with the other talk poster than pictures and animations would better illuminate this subject. --Feweiss (talk) 05:14, 4 June 2009 (UTC)
Synchro/non-synchro vs constant mesh transmissions
The construction of the article implies that non-synchro is equivalent to non-constant mesh (although this point is cleared up in brief in the "Synchro" section). It isn't a simple edit to rewrite it correctly, but it is misleading. —Preceding unsigned comment added by Weasley one (talk • contribs) 09:44, 1 August 2009 (UTC)
I've been looking up information about crash gearboxes, but there isn't an article at this title, nor do the search results provide an obvious location. I think therefore a redirect from crash gearbox would be a good idea, possibly to the Unsynchronised transmission section of this article or is there a better target? Thryduulf (talk) 19:35, 11 August 2009 (UTC)
- Created "crash gearbox" page. It may be best to merge it in to this page, creating one section for "crash box" and one for "unsynchronized non-crash-box" (but with better names!). —Preceding unsigned comment added by Pardo (talk • contribs) 22:33, 2 September 2009 (UTC)
Lexus IS F
Should this really be mentioned on this page? The car has an 8 speed semi-automatic, not a manual. I don't believe it belongs here. A very crude definition of a manual transmission would be one that involves a driver operated clutch -- the Lexus does not have this feature and relies on torque converters to decouple the engine and transmission. Since this serves as the basis for the idea that more than 6 forward gears are available in commercial cars, all references to more than 6 speeds should be removed. Willing to retract this opinion if someone can find a picture of an 8 speed gear shift in a Lexus IS F that does not involve paddle shifters and clearly shows a clutch pedal. 126.96.36.199 (talk) 03:45, 17 December 2009 (UTC)
"The NHTSA reports that manual transmissions also result in 37% fewer accidents per mile driven. Experts believe that this is due to the extra attention required while driving a stick-shift. For example, it is difficult to use a cell phone while driving a manual transmission."
"...automated manual and semi-automatic transmissions are becoming more common on heavy vehicles, as they...may improve safety by allowing the driver to concentrate on road conditions." —Preceding unsigned comment added by 188.8.131.52 (talk) 22:59, 22 December 2009 (UTC)
Well, it depends on the driver. If one usually takes the risk to use a cellphone while driving, then a manual gearbox will make a drive with that driver a bit safer. If phones are not an issue with a driver, then he can concentrate more on the road. But honestly that is complete crap, because when you are OK with the manual gearbox, it doesn't distract you even a bit from the road. —Preceding unsigned comment added by 184.108.40.206 (talk) 22:05, 12 February 2010 (UTC)
there are not many statistics about manual vs automatics from a safety standpoint and the "NHTSA study" mentioned seems to have been a fictitious creation unless the NHTSA for some reason buried it. however there was a study done by the University of Virginia which showed a vast improvement of safety with manual transmission in people with ADHD. here are several links to articles referring to the study.    —Preceding unsigned comment added by 220.127.116.11 (talk) 20:12, 17 March 2010 (UTC)
One drawback is not a drawback, propose removed from there
Almost half of the "drawback" section actually talks about the need of driver's expertise to operate a manual gearbox as of a drawback. But wait a minute, since when an expertise requirement in any given field is considered a drawback?! That is just a particular characteristic of a manual transmission, and in no case should be placed under "drawbacks". Followng this logic, the ideal car is the one that you get into, tell the car where you wanna go, and just sit and do nothing.
I propose this "drawback" is removed from there and placed in a new neutral category, or at least marked as neither a benefit, nor a drawback. —Preceding unsigned comment added by 18.104.22.168 (talk) 22:01, 12 February 2010 (UTC)
- I disagree. Think of it in reverse, is it an advantage if the need for a skill is removed by a change in technology? I would assert that it is which then makes the requirement for that skill is a drawback, assuming that there is an alternative device that does not need that skill. CrispMuncher (talk) 23:14, 12 February 2010 (UTC)
- I guess you could argue that it's easy to overstate the expertise needed to drive a manual car. I mean, it's not as if significant numbers of British people (for instance) are prohibited from driving because they can't "master the skill" of using a manual transmission. It's really just a different way of driving the car, it's not really any more difficult once you get used to it. Does walking up a flight of stairs demand more skill than using an elevator? There's certainly more involvement on the part of the person walking up the stairs, but it's not something only a skilled person can do. Blankfrackis (talk) 01:01, 13 February 2010 (UTC)
Yeah, Blankfrackis is right - once you master the manual gearbox, it's in no case more difficult than something else, you even stop paying attention to it and switch gears automatically (sorry for the pun). And the example with the elevator is great.
@CrispMuncher, the problem is that the automatic transmission is not an equal replacement for a manual gearbox. While it does the job of switching gears, it deprives the driver a great deal of control over the vehicle (not only in the realm of switching gears), and unless the driver is a "passanger with steering privileges", the automatic gearbox won't do a lot for him/her. The automatic gearbox is just a sort of a compromise for those who are lazy enough, or are just unwilling to use a manual transmission.
It's just that some people don't really care about what control they have over their car, they just want to get from A to B (and are not really drivers, but "passangers with steering privileges", as I said above), but you can't say that that is the way things should generally be (and a manual transmission is an outdated technology). And they're always going to be discussions on this matter because of the initial assumptions of the sides: some people assume driving should be made as easy and less involving as possible, until we have complete auto-drivers, and the others just like the very process of driving a vehicle, and while they'd like that process to be facilitated by different means, e.g. computerization, they wouldn't like parts of the control or the process of driving be taken away from them.
There are benefits and drawbacks to everything. Since when is requiring expertise a drawback? Since always. A drawback doesn't mean that it is worse than something else, a benefit doesn't mean it is better, it is just something to consider. --RLent (talk) 18:04, 18 August 2010 (UTC)
It absolutely is a drawback, no question about it. I can tell you a list of licensed drivers I know who cannot drive manuals, and zero who cannot drive automatics. None of us are saying that they couldn't learn, but if they needed to drive somebody to the hospital in a hurry, they simply could not drive a manual. That's a drawback, they require more training, and in a city like San Francisco, a lot more experience even once somebody learns. It's nothing to get defensive about, it's just a fact. Further proof that it's a drawback is that teaching a beginner to drive your manual will generally shave ten thousand miles off the life of your clutch too. Borrowing a friend's car often leads to some neck flexing startups too, as some cars have quite stiff clutches and other soft, it's a flawless transition, and it's also bad for the clutch. 22.214.171.124 (talk) 22:48, 11 September 2010 (UTC)
- If they needed to drive a motorcycle to the hospital in an emergency they probably couldn't drive that either, is that an intrinsic problem with motorcycles? It's about experience with driving something - in general it's easier to make the transition from a manual to an automatic than it is to go in the other direction, but there are also nuances with an automatic car that require experience as well. Just because fewer people have that experience doesn't make it a drawback as far as I'm concerned because, just like a motorcycle, it's not actually any more challenging, it's simply less used.
- Incidentally, the reason why some people get defensive about this subject (not that I am in the least) is that there's a real tendency amongst people who have never driven a manual transmission to grossly exaggerate how difficult it is to master. It's more the fear of the unknown than anything to do with the transmission itself. Blankfrackis (talk) 14:30, 15 December 2010 (UTC)
- I don't think it's really relevant how many people know how to drive auto versus manual, or car versus motorcycle. Sure, there are a couple of scenarios where me owning an automatic (even though I'm more comfortable with a manual) could be beneficial, such as if someone needs to drive me to the hospital in my car, but the reality is that most people drive their own cars with whatever transmission they prefer, not my car with the transmission I prefer, so these scenarios are the rare exception, not the rule. Furthermore, if it's really an emergency, there's this awesome thing called 911 service. If it's important, but not that important, in just a few minutes I can teach almost anyone to drive a manual well enough to get me to the hospital. Put car in gear, ease out on clutch until car is rolling, apply throttle. Push clutch in, shift gears, let clutch out. Failing that, press throttle to floor, dump clutch, let go of throttle when the tail end starts coming around or we're up to speed. Ignore the clutch wear and bucking car because it's kind of minuscule next to me dying over here. Yay!
- In reality, it's not much harder than that even when we're not dying, but it does take weeks or even months to get consistently smooth with the manual transmission, and can be intimidating for the novice, and it's this learning curve that makes it a disadvantage. As a "car guy" who's driven more manual cars than autos, I think the disadvantages hardly equate to the advantages, but the article isn't about biased preferences--it's about the reality that it is, actually, harder to learn a manual than an auto.126.96.36.199 (talk) 11:28, 9 March 2011 (UTC)
- I think the question isn't so much whether it's harder/more difficult to learn, but whether that's significant enough to mention it as a disadvantage in the article. I mean lots of things are technically harder to learn than an alternative - e.g. tying shoelaces is harder than using velcro shoes, but it's so easy to master that skill that virtually everyone over the age of five uses shoelaces rather than velcro. Would that merit a mention in the article on shoelaces? The main difference between those two examples is simply the amount of people that use the two alternatives, not how difficult they are. If there were a culture (a strange one, granted) which only used velcro shoes, we might have a similar argument. 188.8.131.52 (talk) 14:12, 9 March 2011 (UTC)
The article talks in several places about how R facing to the back is intuitive, and R pulling toward the driver and up on a column mounted shifter is not. All ridiculous. If R is intuitively placed, then 2nd and 4th are counterintuitive? It's silly. And pulling toward the driver on a column mount is toward the back of the car, which I would not call intuitive but whoever wrote it should have. 184.108.40.206 (talk) 22:48, 11 September 2010 (UTC)
Benefits and Drawbacks Section
Ok, so the Benefits and Drawbacks Section was rather difficult for me to read, with seemingly no aim, and several redundancies in unrelated paragraphs. As such, I took it upon myself to re-organize it with a more topic-based approach. I mostly just re-organized what was already written, but added a couple things that seemed to fit. I tried adding some citations, but after checking the External links guide, none of them really seemed to be appropriate, so I removed them. I was unable to find any good cites for anything, but from personal experience I didn't see much that was wrong. Still, a couple things struck me as odd:
All automatics I've driven have had options to put the transmission into 2nd or 1st for engine braking downhill. Most have also had the option of 3rd (usually by way of "turning off" the overdrive, which is just 4th gear - though the "OD off" button often changes the dynamics of the transmission as well). As such, I think the section about "Nissans and Hondas" having such options should probably be generalized to "most automatics" or something similar. In fact, given that most automatics have the ability to do this (as well the part I added about downshifting to pass in the "performance" section), it might be better to re-word this to something like "it's more obvious and common to do this with a manual". This last statement is based on many internet posts I've seen asking if engine braking is safe for an automatic, meaning A, people don't read the owner's guide, and B, it's not very obvious to many people.
As pointed out above (or below, I'm not sure which way wikipedia orders these sections), using the starter on a hydro-locked engine can be fatal to your motor, very quickly. The only way this is useful is if you pull out all the spark plugs first, which also happens to be how you get the engine running again so it can pull itself out of the water. Furthermore, most vehicles that are meant to be off-roading have winches attached for this very reason. As such, this part should probably be deleted. Still, I'm not an off-roader, so it's possible there's something to this--perhaps the water didn't get into the motor because the guy used a snorkel, but the back-pressure on the exhaust is preventing the motor from spinning fast enough to run.
I probably won't ever read this page again, so if you have better ideas or hate my version, revert or change it. It just bugged me because I was having a difficult time understanding what the article was trying to say here (I also made a couple minor edits to other sections, but just some typos and stuff). 220.127.116.11 (talk) 10:38, 9 March 2011 (UTC)
Many vehicles offer a 5-speed or 6-speed manual, whereas the automatic option would typically be a 4-speed. From the year 2010 4-speed automatic are not to be the most often option automatic. Need to update the article — Preceding unsigned comment added by 18.104.22.168 (talk) 22:12, 5 February 2012 (UTC)
The drawbacks section reads like a fly-by screed by a guy who doesn't care for manual transmissions. It should be improved with sourced material or deleted. This isn't a soapbox. — Preceding unsigned comment added by Jdfulmer (talk • contribs) 13:54, 1 March 2012 (UTC)
I still find this section problematic. For example, the "Performance and control" section under Advantages mentions neither performance nor control. It's not obvious, at least to me, that merely having more gears available aids either. 22.214.171.124 (talk) 02:57, 7 May 2012 (UTC)
There is mention of Subarus and hill starts in this section, which mentions the computer applying varied braking force. I don't know about more recent Subarus, but I'm fairly certain my 2002 Outback did this entirely mechanically. Braking pressure was retained at the level the driver applied after the clutch was pressed in, even if less than required to hold the car. The pressure is released practically instantly when the clutch is let up to a certain point. The system will even engage with the engine not running, which I would have thought unlikely for a computer driven system. 126.96.36.199 (talk) 04:05, 9 September 2014 (UTC)
Illustrations at the end
They are quite nice, and surely appear to have been prepared by someone who knows enough. However, they really need to be about twice the size, or more! I find it hard to figure out where the output shaft is, for instance, having a good technical background, but not knowing what's commonplace. I do hope they can be enlarged without becoming too "grainy". As well, a few callouts, such as "Input Shaft From Clutch", "Countershaft", and "Output Driveshaft" would be quite helpful. Just to give some perspective, I was looking to see which gears were engaged, and it was a lot harder than I think it should have been to find them. Best regards, Nikevich (talk) 07:26, 13 October 2011 (UTC)
Revised "complexity and learning curve."
I recently made some changes to the "complexity and learning curve" section under Drawbacks. I also moved the part going into reverse gear while the vehicle is in motion to the second to last paragraph under the "Reverse" section.
Lots of clutch use in heavy traffic? Not true!
Unless the car comes to an absolute stand-still, there is no need to use the clutch. Usually the second gear has a lot of "range", all the way down to a fairly slow creep. If you do not tail-gate the car in front of you, and look at the traffic ahead, you can stay in gear and keep moving, just using the accelerator pedal. It can be less work than an automatic, where you have to alternate between gas and brake. Also, if you do press on the clutch, anticipating that you might have to stop, but do not actually stop, you can just release the clutch while the car is still rolling. This is quicker and easier than a start from a full stop; you don't even think about it. 188.8.131.52 (talk) 21:44, 29 July 2013 (UTC)
- I would not say that at all. I always have to reposition my foot after I have clutched-in (engaged=>released pedal), because I use the "anchor to ground + rotate" technique which is the most precise and less tiring (foot resting on ground). Some people are using "lift leg and accompany pedal" with the foot not touching the ground, in which case it gets tiring, but you can clutch-out/in indefinitely. The first technique has the inconvenient of having your shoe sliding down the pedal's surface, making it impossible to immediately re-disengage (push) without fully releasing your foot first (and thus engaging clutch) and re-pushing it with the proper position on the pedal. While I understand the argument that indeed it could be possible to have less work than the automatic, and certainly less danger of bumping cars in front of you (because not braking an automatic results in slow forward motion, hem...), it still is more work and pretty tiring with time, with any of the 2 techniques above. Lightness1024--184.108.40.206 (talk) 06:37, 3 June 2014 (UTC)
I haven't read the whole article but the bits that I have seem to have a heavy American bias such as standards, car references (e.g. Buick, Pontiac, Caddilac are not common cars outside the U.S.) and road references, etc. Perhaps some sections could be rewritten for a more worldwide view (by addiition not subtitution)?Angry Mustelid (talk) 23:07, 10 May 2014 (UTC)