In the Clutch..or Not

[amazinblue82]

I hijacked my own thread .."Scenicruisin" .. trying to learn about something new to me.

Clutchless shifting a manual transmission. I been reading about it this morning with a mix of fascination and trepidation.

Learning that professional truck drivers routinely go "clutchless" was surprising but reading up on it it seems to make sense to me.

That you could do it in your car was a real surprise. I have/had many manual transmission cars and have ALWAYS used the clutch. That's what my Dad taught me..that's what I taught my daughters.

If this thread gets 10 posts or so that might be enough data points for a consensus on this topic. Thanks for anyone's views in advance.

Two short videos below are self-explanatory.

Questions: Do you use the clutch in your passenger cars (or trucks)? Risks (e.g., chewing up synchros?) or rewards (e.g., saves time and fuel?) of your preference/practice that you've experienced?

https://youtu.be/w_8kOQv4V8Y

https://youtu.be/jLw0hAtOik4

 

[BIGBARNEYCARS]

Had ah friend(An executive at world Headquarters) bring an '89 TC 16 valve 5 spd. home for the weekend when they 1st came out then handed me the keyz and said letz go for a spin to see if you like it. This waz in Dearborn not far off the intersection of Ford road and Telegraph and once I pulled out of hiz drive way the only time I touched the clutch waz at ah few stop signz where I had to. After about 20 of driving around the west side of the Moter City he realized I wasn't using it and went ballistic. Accused me of trying to get him fired. He also ask my for the keyz back and wouldn't let me drive back to hiz place. And I just kept laughing all the way back there, Jer

 

[Big_John]

The last stick car I had was a Dodge Stratus. I used the clutch on upshifts and usually didn't on downshifts. That was more about the arthritis in my left foot than anything else.

 

[commando1]

Definition of a clutch:
What you need when at a red light and when drag racing.
That's all.

 

[amazinblue82]

i guess car manufacturers' DONT advise it because for a majority of drivers its an "acquired skill" (i.e. clutchless shifting) they would rather we NOT practice?

aside, wonder what the Peterbilt owners manual says about itranny operation?

anyway, people that can do it make it look easy...the videos show that either that's because it IS easy and ya just gotta try it and you'll pick it up, OR because its NOT that easy and it takes some hand/foot/eye/ear/seat-of-the-pants skills that may elude many of us?

 

[70bigblockdodge]

I don't remember the wording in the Peterbilt manual, but I'm sure it did not acknowledge that anyone would shift without the clutch.

 

[BIGBARNEYCARS]

Ray, If you ever put your foot on the clutch peddle in ah large car and had to almost bend the frame on the Bostrom (the Chair) to depress the clutch you'd know why we all picked up the habit of clutchless shifting. If any of us in the trade were ever laying on ah paddle board and kickin' in the water we'd all be makin' right turnz and that'z the truth, Jer

 

[amazinblue82]

again i came from a knowledge/practice base of clutch users. heck my dad had a truck he "double-clutched". what a pain in the arse i thought ...and i was only ten years old.

this is interesting...i was taught "10 o'clock, 2 o'clock" in driver training as a 15 year old. after passing my road test, i never did that again to this day (except in bad weather). car steered just fine..no arm fatigue, no danger .. and I looked cool like my Dad who drove with only one hand on wheel.

but I was told that clutchless-shifting wears on some of the tranny parts (where applicable - synchronized setups), easier to stall the car, high potential to grinding gears which is clearly bad AND distracts the driver...all true IF you don't know how to do it?

so where's the harm in clutchless, or since most of us do NOT drive for a living, its just a thing we don't/didn't need to learn?

 

[amazinblue82]

Page 86 of this.

http://www.peterbilt.com/resources/...l Trucks Operator's Manual prior to 12-06.pdf




this is "proof" of nothing..i am just following the bread crumbs of my own question about what a Peterbilt manual says. Date is December 2001 so there are clearly newer publications.

Double Clutching

Whether you are upshifting or down shifting, it is best to double clutch. Double clutching is easier on your transmission and on your engine, helping your vehicle match engine speed with driveline speed and achieving clash-free shifts.

To double clutch:

1. Push down the clutch pedal to disengage the clutch.
2. Move the gear shift lever to neutral.
3. Release the pedal to engage the clutch. This lets you control the RPM of the mainshaft gears. Thus you can match the RPM of the mainshaft gears to those of the output shaft.

Upshifts - Let the engine and gears slowdown to the RPM required for the next gear. Use the tachometer to determine optimum RPM for gear engagement.

Downshifts - Press accelerator to increase engine and gearspeed to the RPM required in the lower gear. Use the tachometerto determine optimum RPM for gear engagement.​

4. Now quickly press the pedal to disengage the clutch. Move the gear shift lever to the next gear speed position.
5. Release the pedal to engage the clutch.

 

[70bigblockdodge]

Yeah double clutching is how you are supposed to drive a big truck. That brings up the point that I forgot to mention is that big truck transmissions do not have synchronisers and or brass/bronze blocker rings as some call them these are a wear item in a car or light vehicle which allows the slide gear to grab ahold or slow down the shafts and the attached gear allowing the slide gear to engage selecting that gear. Big trucks do not have these because they would last about a month, the gears are large and heavy, the clutch plates weigh as much as the whole clutch assembly in a car, there are two countershafts to splits the 1500-2100 ft-lbs. Coming in the input shaft and keeping the case from cracking open. This is why using the clutch or not in a big truck you still have to match the engine rpm to the gear you want to get it to engage.

 

[amazinblue82]

Yeah double clutching is how you are supposed to drive a big truck. That brings up the point that I forgot to mention is that big truck transmissions do not have synchronisers and or brass/bronze blocker rings as some call them these are a wear item in a car or light vehicle which allows the slide gear to grab ahold or slow down the shafts and the attached gear allowing the slide gear to engage selecting that gear. Big trucks do not have these because they would last about a month, the gears are large and heavy, the clutch plates weigh as much as the whole clutch assembly in a car, there are two countershafts to splits the 1500-2100 ft-lbs. Coming in the input shaft and keeping the case from cracking open. This is why using the clutch or not in a big truck you still have to match the engine rpm to the gear you want to get it to engage.

ah..that NOW makes even more sense to me then...NO "sychronizers"..why clutchless-shifting in a big truck is technically more feasible versus a car. obviously it can be done it cars but thats why some warn against it...unless you are expert at doing it.

when it stops raining here today, i am still gonna try it in a car for the first time in my life. shoot if that kid in the video can do it, so can I :icon_pirat:

 

[70bigblockdodge]

Yeah sorry about that its all such second nature in the truck you don't really think about what is happening inside the transmission. I see that none of the other truck drivers realized that was the missing piece to make it easier to understand, for the same reason I suppose.

 

[amazinblue82]

Yeah sorry about that its all such second nature in the truck you don't really think about what is happening inside the transmission. I see that none of the other truck drivers realized that was the missing piece to make it easier to understand, for the same reason I suppose.

no apology needed man.

When I have the knowledge to pass basic ideas along, I many times leave out key details because they are SO basic to ME it just doesn't come to mind.

Like when you tell someone to "start the old C-body up", you don't add "turn the key"...you are pretty sure they know that already.

i aint smart (on diesels and big trucks), but I CAN read and then I can GET smarter. thanks for stayin' at it for me.

 

[live4theking]

This is kind of interesting...

I cannot tell you the last time I used the clutch up shifting my motorcycle. I do use it down shifting though because you don't have neutral between every gear. I've driven my Cherokee a lot without the clutch. As a matter of fact when I was teaching my wife how to drive it she was paying way too much attention to how I was driving with the clutch instead of learning to listen to the engine so I started shifting without the clutch. That frustrated her but got the point across that you need to listen to the engine instead of watching the tach and worrying about every other little thing being perfect.

 

[300rag]

The only issue when not using a clutch in a recent model is that the time it takes for the RPMs to drop is controlled by the computer to help with the emissions. They don't drop like in the old cars, so it takes a little more finesse to do it without a grind.

 

[Big blubber]

I Clutchless shift on my Zx 10 all the time ,I just match the engine revs it gets second nature after a while :yaayy:

 

[Xenon]

I don't seem to have a problem in a new SRT shifting w/o clutch...
But then,, I have been shifting w/o clutch for many many many,, years...

 

[barnfind]

Dont forget about your trans brake

 

[amazinblue82]

I don't seem to have a problem in a new SRT shifting w/o clutch...
But then,, I have been shifting w/o clutch for many many many,, years...

no issues with the ECM "slowing down" the RPM falloff as 300rag pointed out. or you just compensate for that with experience?

 

[amazinblue82]

Dont forget about your trans brake

significance of this element if you get a chance to bounce back?