Changing the Gears in an Automobile Without Use of the Clutch Mechanism

Hard to say it better.

But a little shorter: yes, with much technique/coordination. (The brute version is called "gear-jamming.")

yes it is but i need to change while the engine is running

• ya what my aim is that i wanna shift the gear without using the clutch in the motorcycle and my gearbox should be as usual without any damage one-more thing that my gearbox life should be as usual as given by the manufacturer

In a motorcycle it's much easier and damage is less possible (chain backlash and lower inertia plus shift lever spring helps), but why would you do that unless you had to? S.M.

?? I haven't been a biker for some years, but I don't remember a clutch lever.

i just want to engage the gears while they are running how can i explain briefly

Ok I see no reason doing that except a busted cluch cable etc but here it is: In motorcycle to minimize damage risk, it's a little different approach. All shifts MUST be done at times the engine gives or receives minimum torque i.e if engine would be disengaged it would stay at about the same RPM. A liitle more throttle when down-shifting and a little less when up-shifting and that's all. Chain backlash will handle shock, but you still have severely more stressing on gearbox components than in normal use. Why? S.M.

I hope you have a spare gearbox - it sounds as if you'll wreck the first one learning the technique.

The ideal is to get the speeds of the driving and driven gears equal, and not to try changing while the engine is actually accelerating or decelerating the bike. It's easier to learn in a car, where you can change into neutral while matching the speeds. If you are experienced on a bike you'll learn (from the engine tone, current gear and road speed) how to do this - eventually it'll become second nature. But leave plenty of time to do it - the last thing you want to do is end up going into a bend in the wrong gear.

When starting (i.e. going into first gear) your only hope of not damaging the gearbox is to have the bike rolling before trying to engage.

(Oh, by the way - your thread title says "automobile" (which usually implies a four-wheeler), but you seem to be talking about a motorcycle - please clarify).

i agree. i've done the same with my dirt bikes in emergencies and never had a problem, but auto trannys don't have strong enough sycronizers to hold up very long. why would you want to shift without a cluch? i would'nt think it would last long. cluch plates are fairly cheap if it needs rebuilt.

Looks like about a one hour job. I'm sure you could google and find directions specific to your motorcycle.

http://www.youtube.com/watch?v=s-haQMsOvE0

From your post #5:

"ya what my aim is that i wanna shift the gear without using the clutch in the motorcycle..." Is it a motorcycle, or an automobile per your thread title?

"...and my gearbox should be as usual without any damage..." Best of luck with this.

"...one-more thing that my gearbox life should be as usual as given by the manufacturer" I am certain the gearbox manufacturer will say something like "Use the clutch, or warranty is voided".

I have done this many times. The final piece that makes it work is you have to start the engine in first gear and sync the torque on the tranny to 0 to slide it out of gear before you break to a stop. Driven many miles that way after a clutch failure. The biggest problem can be starting it on an uphill grade.

Excellently said. In support of your answer, I first did it on a '60 chevy with a weak 6 cyl engine, always worked (including starting it in 1st or rev.). Traded in the car with 150K miles on it and dealer thought it had 50K on it. Since then I have owned Triumph TR-6, Austin-Healey 3000 mk 3, Datsun 280 ZX, Toyota, Ford Mustang, Chevy truck, driven many others and with each I was consistently able to shift without the clutch. After the thrill was over I continued to do it out of laziness more than anything else.

Never met a tranny (stick that is) that it couldn't be done on other than old cantankerous trucks which had to be double clutched.

Old Salt

Double clutched? Ah, you can't fool me. One of them is the brake!

Back in a previous life I drove truck from coast to coast. I used the clutch to get started but after that I never touched the clutch again until I came to a stop. The old timers then would give you hell for wearing out their clutch if you "double clutched" or used it at all. It was a sign of an experienced driver if you could shift a 2 stick 4 X 4 transmission smoothly without the clutch. More than a million miles and I never had a problem with either a clutch or tranny.

Rich Hurd

Surely this thread is just bonkers?
It should read "How do I mend or temporarilly rig my Clutch?".
And ideally refer to all the pertinent details.
Or am I missing something?
Del
<click> Grumpy mode OFF... nah, sod it <click>, back ON

Observation: There are people who really have a "short-cut mentality" (for they don't like to follow standard operating procedure (SOP)) and another is: if you found an answer to a querry, they will shift to another to disregard the previous subject as if it was wrong and doing so have to proceed to another discussion.

As an engineer, we should follow SOP and no shortcuts.

Or am I missing something?
Clearly, you have not been taking your catnip on schedule. Shifting without the clutch is common on motorcycles. The OP just wants to learn how to do it. His friends are beating him in races, and he feels inadequate. If we fail to help him out, he could become depressed, and possibly suicidal.

i tried this with a company truck a while back. it did'nt have 50 miles on a chevy heavy duty 4 speed. i thought i was doing a great job shifting at a certain rpm without using the clutch. by the time i made it back to the shop "75 miles", the syncronizers were junk and the tranny needed a complete overhaul. i would'nt recommend doing it.

You must have the right FEELING! The sinchro rings will not be damaged at all if done right.

I changed gears on old farm tractors with "crasch boxes] and they do not even have any sinchro. Shifting up and down.....A bit tricky with the hand throttle with worn links!

Better learn to shift without clutch, you might be forced to one day!

It can be a very useful skill to learn. The clutch cable broke on my pickup truck and the only way I could get home was to shift on the run. all that is necessary is to syncronize the input and output gears before changing gears. At a stop, I had to shut off the engine and start the engine in gear.

It's actually really easy on the large tractor trailor trucks... it's just the 1st gear that can be a pain... I actually know many old truck drivers who only use the clutch in 1st gear, and once rolling never touch it again... but those are old experienced drivers running old trucks, who know exactly what RPM's work for each gear.

On all the dirtbikes/quads Iv'e ever driven, it was only 1st gear I ever used the clutch for... all the other gears i just hit on the run, and I've never had any problems...

When I was a kid I worked for a cantankerous old rancher. When I was old enough (about ten years old I think) he wanted me to drive one of his equally old and cantankerous trucks around the place for varied chores. Taking me through the basics of driving, he says "Now, the tranny is a little creaky, an' ya might hafta double-clutch 'er. Do ya know about that?" Anxious to show wisdom beyond my years, I said "You can't fool me. One of them pedals is probably the brake!"

It used to be an old Rallye racing trick.

Not needed anymore cuz now they have sequential gear semi automatic shifting.

Again it used to be an old grand priz superbike racing ... it's totally possible the only problem is that you will need a few gear boxes before you get the handle of it.

Try it ... see what happens ... not that you gonna die or something like that ...

:)

A friend of mine ran a classic VW bug daily in the city for 5 months with no clutch. He started the engine in 1st or reverse, and shifted with care and finesse. Good starters, those.

Whether it be a transmission in a car, truck or motorcycle, the key element is make certain that the engine speed be raised with the gas pedal when shifting down or allowed to fall to the proper speed when shifting up.

It's difficult to describe, however, if you have driven the machine for any length of time, then you should sense intuitively what the engine speed should be, before you select that gear.

Were this an old style crash box on a forty year old car, you'd be double clutching anyway. Nowadays, bronze conical synchronizers force the engaged gear up to speed anyway so double clutching is no longer an imperative operation.

To the best of my knowledge, motorcycles do not use balk ring type synchros. Why I don't know.

In any case, I think it prudent to at least learn how to shift without using the clutch.

If the slave or master cylinder fails on a hydraulic clutch, or as someone already pointed out, the clutch cable breaks, you'll be able to shift up and down with little effort and without damaging the gear box.

The most important aspect of this entire discussion has already been pointed out: do not allow the car to be loading the gears under deceleration or the engine to be loading the gears with power. So long as you are in the "sweet spot" between the two, neither your gearbox nor your wallet will complain.

L.J.

Motorcycle gearboxes tend to be of the 'dog' design. This means dogs will disengage and engage in a zero torque window, with just light pressure applied to the leaver.

Throttle skill is required, but is easily learned. The main danger is accidentally jumping 2 ratios when down shifting, which tends to lock the rear.

If you want the gearbox to last only use the technique in cruse mode, not race mode, until very good at it.

Gentlemen, let hit the nail directly on the as the question goes, [a] change gear without the use of clutch [b] without stopping the engine [c] without any damaged to the gearbox or what ever, The answer is NO. as there are tendencies of damaging the Gear box, the driving shaft universal joint for vehicle or the driving chain/sprocket for motor cycle

I short shifted all manual trans cars after 1st gear, Upshift and down shifted with exception of the Datsun. Linkage was just too loose to do so except from 4th to 5th and 5th to 4th. After that, had to use the clutch. Miss my 5 speeds!! Always got neat 50 MPG with them after a little engine work. Now driving a 4X4 truck @ 18.5 MPG best I can get out of it... Looking for a 7 speed now.

Do a web search for '6 speed clutchless', 'Keisler' or similar and you will find many references (mostly YouTube) to clutchless transmissions.

Whether this answers your question or not, is anyone's guess...

Steve.

That's ok for a box where you can change from any gear to any other via neutral.

Not applicable to motorbike-type gearboxes, where (usually) neutral is between 1st and 2nd. Above 2nd, shifting is sequential (2-3-4 etc.) with no access to N.

3: Take your time and gently push the levertowards second gear, at the same time gently open the throttle until your engine revs match the gear ratio and road speed.

Actually, this adding of throttle should not be necessary. You should reduce throttle to disengage the lower gear, allow the rpm to decrease to the match speed for the next gear, and flick the lever into the next gear. Then immediately get back on the throttle. This should take no more than 1/4 second, and should require no more force than in normal shifting.

In going from first to second at a particular speed, the engine must go from say 3000 rpm to 2200 rpm. There is no need to add throttle to get the engine up to speed, unless you have failed to engage second gear quickly enough (with the rpm on its way down), and allowed the rpm to drop toward idle. That would be bad technique, and would cause unnecessary wear on the synchros as you hunt for the correct rpm (in the "gently push the lever towards second gear, at the same time gently open the throttle" segment.)

When shifting clutchless in a car with synchromesh, it is best to think of the car as having no synchros at all. Precise timing and perfect speed matches will give you a fast, reliable shift that does not rely on the synchros to match shaft speeds.
Done correctly, the synchros have no work to do, the clutch has no work to do, and the shift will sound like those on a double-clutch Porsche, with just barely perceptible pause in power delivery.

Most bikes have lightweight constant mesh gears and consequently make clutchless shifts easy. Anyone whose ridden quickly would be able to tell you that. Naturally, I excuse two wheeled tractors (Harleys).

Do you have experience at this? There is no real point in rushing things when a beginner. Most people tend to allow the revs to drop too far. Perfect commenters excepted of course.

Do you have experience at this?
Sure. Maybe 50,000 shifts this way in cars (1000 done of necessity, the rest for fun.) 100 grinds, all the rest worked fine.
Most people tend to allow the revs to drop too far.
True; they shouldn't do that -- it just makes the synchros try to synchronize speeds, which (because the input shaft is connected to a very large rotating mass) they cannot do. Thus, hunting around for the right speed wears the synchros unnecessarily.

All this is fine but remember the initial inquiry came from a novice so taking it easy is probably best for now. This is thecontext of my answer. Maybe we sould leave the finer points to another post and not confuse the poor bugger.

Of course, it just takes a little finesse.

Back when I was a teen (in the days of whale-oil-powered TV's) I had an Indian motorcycle, with a failed clutch disengagement mechanism. I'd start moving by pushing a little with my feet, and slip it into first, with the engine at idle. At each shift I would back off on the throttle enough to unload the gears (neither accelerating nor decelerating) and slide into the next gear. Starting off when facing uphill was effectively impossible.

This sort of shifting is common in racing motorcycles, especially motocross. You load the shift lever with your toe, and back off the throttle for the blink of an eye, and the lever moves and the bike pops into the next gear. Some bikes (especially drag bikes) have kill switches rigged up for this purpose, so the throttle can be held wide open, and the unloading is done with the kill switch. The shift takes less than 1/10 second. (Starting off is done by using the clutch normally.) A few race cars also use this technique with "crash boxes," which do not have synchronizers. (Motorcycles also don't use synchronizers, btw.)

In a modern car with a failed clutch disengagement mechanism, the car must be moving before engaging first gear (coasting down a hill, for example). The actual shift has to be done with a little more finesse than with a motorcycle to avoid synchro grinding. I do it periodically to keep up on the technique (which admittedly has essentially zero utility in a car.)

Anyone remember pre-selector gearboxes? You chose the gear you wanted before operating the clutch. When the clutch was actuated, the gear change would take place. I don't recall if it worked while shifting down or just when going up. Remember the heel and toe technique. I could never get the hang of it. Thr pedals had to be the correct distance apart for it to work well.

Thr pedals had to be the correct distance apart for it to work well.
I used right-side/left-side instead, if the pedals were close together. Big toe on the brake, pinky toe on the gas.

Yeah Ron, a mate hade a Wilson box in an old Daimler. He used to tap the clutch twice (like a double shuffle) and the changes were still un-Daimler like. Still, not bad for the 40's

Only the Lanchester and was too young to drive.

I used to do this inadvertently on the mini cooper you see here at the Tropic Line.

The headlight dip switch was located near to where the clutch pedal hung, so yes it was a question of speed matching when you hit the dip and slid the stick.

You need to talk to a good mechanic to find the shift point rpm for the transmission you are driving. For the Cummins-powered 10-speed Kenworth T-2000, the shift points are 1300 and 1500 rpm. Then you have to learn the sound of each point. Accelerate to 1500 rpm, "float" the ransmission into neutral, let the engine slow to 1300rpm, and quickly slip it into the next higher gear. To down-shift, let the vehicle slow to the lower point (1300 rpm for that KW), "float" into neutral, rev to just over the upper shift point and quickly shift to the next lower gear as the rpm matches. I spent two years teaching rookie drivers to do this for Stevens Transport after I retired from research with Texas A&M. In an auto it helps to have a "synchromesh" tansmission.

Psych-os-ic ? Yeah! Sounds better. S.M.

sure, I do with my porsche 911 all the time......except down shifting.

Throttle, let off, shift, throttle, let off, shift, throttle, let off, shift and throttle. Do it as fast as you can say it....no hesitation, and your going about 60 right now.

yes with a van doorne transmission

I reckon the closest one could get to a minimum loss, wear free, continuously variable transmission would be a i.c. motor-generator set driving an electric motor with all the intermediate control performed via a conventional, but extended, elctric drive control. OK, there would be power conversion losses in the electronics but it could be done.

My DAFs were a bit weak and my Aprilia Mana is OK once it is off the line (torque is limited until the clutch is fully engaged and the transmission is 'settled') but is still relatively slow to alter the drive ratio when you accelerate hard from the cruise.