please help me here! ive been told that trucks above the one ton state, use the clutch only for take off, then you just feel your way through the gears ,with out clutching? ive done that with cars and dirt bikes, and was told that it was damaging to do so!
It's generaly done on class 7 or 8 trucks with transmissions that are not syncretized.They use sliding gears or siding clutches.sometimes I take it out of gear with the clutch then let off the throttle until it will go in the next higher gear.It's a smooth transition after you get used to it.
your talking about rpm shifting use the clutch to start and stop. i have done this with an old mack have not driven any of these new transmisions. but i know you can do it in the older trucks
Yep, that's the way you drive big truck trannies. It's really simple why. First of all, the gears are way bigger in diameter and thickness than car or motorcycle trannies, so the mesh is totally different. Second, if you wound out a gear and need to shift to the next high gear, these heavy shafts and gears have inertia almost like a flywheel. If you just pushed in the clutch and try to shift, the inertia has everything turning and you'd still "grind the gear". So you learn to shift by leaving the clutch engaged to keep the engine sync'ed up with the tranny shaft and use the throttle pedal to control engine rpm to match up the gear being engaged. Takes a little practice, but after a while, your shifting as easy and flawless as in a car.
You can shift without a clutch with any manual. I use to do it all the time with the 6spd in my F350, now I have an auto. My dump has a 13spd and only use the clutch when starting.
Not a good idea with syncro boxes, as I have heard that not using the clutch can damage the syncro gears. However yeah, any crash box can be shifted without the clutch, either that or double de-clutch. It does take some practice to get the revs right, particularly on the down shift. On the trucks I drove it was 500 rpm between gears. Once you get the hang of it you can do it in yer sleep. This is best practiced away from traffic as you can easily get locked out and panic. Then there is skip shifting which we will leave for advanced class.
Could be, but I had over 150k miles on that pickup when I sold it and never had a tranny problem. :beatsme
I only use the clutch for starting out. Even at a stop sign, if I don't have to wait for anyone, I can drop it into a low gear just as the wheels come to a stop without using the clutch. When empty I skip shift a lot without the clutch. A lot of times I only use 4 gears when empty.
This reminds me of a joke I heard a long time ago, not sure if I got it right but here it goes: One fine day a cop pulls over a bloke in a fancy red convertible sports car, cop says to the fella "you know there was stop sign back there and you failed to come to a complete stop" yuppie says "ahh come on now officer I slowed down and just about came to a stop" Cop pulls the driver out of the car and starts pounding him with his stick, after a while he asks the driver "now sir would you like me slow down and almost stop or would you like me to come to a complete stop?"
Hey counter, I'll kick it up another notch above "clutch or no clutch", and give you "no clutch and no throttle pedal". Back in the late '80s, I worked for a crane company. An operator called on the radio and said the hyd clutch pedal on the TMS100 Grove crane dropped to the floorboard, no clutch control. Then his throttle pedal did the same, linkage broke, had no throttle. He pulled over on the side of the highway and requested a wrecker. I radio'd back and said "I'm on my way, I'll get it back home". When I got there he asked "how are you going to drive this thing back?" I said "drive my truck and follow me." On this crane, the only thing between you and the engine is a piece of sheet metal access cover. I removed the cover, and there's the engine right next to me. I put the machine in low gear and hit the starter. It fired up and started moving. Reach into the engine and work the throttle control to wind up the gear with my right hand while left hand is on steering wheel. Take left hand off wheel to shift to next gear while working throttle with right hand to mesh gears, holding steering wheel with left knee! I drove this thing about 15 miles back to our shop like this. Machines ain't nothing like cars or motorcycles.
I've driven all the trucks in my career without a clutch for shifting, both up and down. A synchromesh tranny can be damaged in this manner if you rely on the synchros to align the gears rather than engine rpm and try to muscle it into gear. If done properly there shouldn't be any additional wear.
Yeah that makes sense, as synchro gears are not as tough as the actual gears.
I learned how to float the gears way before I learned how to double clutch. Once you've done it a few times in your particular truck, you just do it by ear and feel. Saves wear and tear on the clutch linkages, and on the ol' left knee too!
Had a similar event to atcoequip's, also in a crane. TMS 300, had clutch pedal, but the throttle when it was below 10 degrees would stick wide open. Crane is a single engine for upper and lower and I found I could shift by pulling the throttle control air switch from upper to lower. Button out, full throttle, push button in to throttle down while shifting to idle down, shift, then button back out for full throttle. In a 13 speed. When I explained to the mechanic how I was getting back home in cold weather, he smacked me in the head and told me to quit driving it that way. I told him if he would find time to fix it when I wasn't out making money, he could have at it, otherwise I was waiting for a slower day. So yes, shifting is possible with no clutch, also with no throttle, and other assorted things that most consider as vital to road use.
Ive driven manual trannies my whole life and ill tell ya with syncro's its alot easier with the clutch but driven my class eight the clutch is only used when im starting or stoping.
That's a funny story. Sometimes a crane operator is required to operate things other than...just the crane, like upper/lower throttle control switch's so you can shift gears and get back in the throttle.
Crane work is never boring.It's a multitasking job.
We had a crane operator that must have figured it was boring! We were setting up a batch plant and had to take some time to assemble some stuff and when we finally got done we were signaling to the operator to go ahead and raise it up. kept trying to get his attention only to find out he had fallen asleep!! We were not very amused
I had a crane job like that last summer. I was setting trusses on a new home and the carpender had a string stretched acosse the top of the peak.He took about 10 to 15 miniutes to set a truss.I would shut the crane off and wait untill they were ready fore the next truss.Oh well ,I was charging by the hour.
Boy - these guys are taking for-ev-er to get this batch plant ready. I already ate most of my lunch. You think they would be ready when they're paying by the hour? Radio is kind of boring. Hmmm - maybe I'll just close my eyes for a little bit ....a little more.........maybe tilt the seat back...... zzzzzzzzzzzzzzzzzzzzzzzzzz. Just fooling with you. I actually can't sleep in the cab, but I used to work with a operator who claimed he could sleep while actually swinging the crane! I never saw it, but I do know if he was sitting still very long, you better plan on waking him up.
I worked for a digging outfit that had a operator who would fall asleep at the controls of a machine. I have heard from multiple people who had worked with him that he would fall asleep and wake up in the middle of swinging to load a truck, or while making a cut with an excavator. They also said that when he did it you couldn't tell where he had stopped then restarted he'd been doing it for so long.
clutch, or not thanks for the replies!!!!so im to take it that clutchless shifts are the norm on the big stuff! though ive had clutchless shifts in cars and bikes that were way smoother then using the clutch! please send me in the right direction!
Yeah, that's pretty much the way it works. And thankfully so, you have to consider this; whether your driving a dump truck, semi-, crane, any big truck, your driving something that will weigh somewhere around 50 to 80 thousand pounds and will have a tranny with as many as 18 gears. If you had to shift all those gears, starting and stopping for red lights, doing this all day long, the old left leg/knee would be killing you using a clutch all day! Thankfully, clutch is only needed for getting started. After that, it's all in how you work the throttle pedal.
Generally in a syncromesh gear box you use a clutch once per shift and in a crash box you double de-clutch while you are learning to get the feel between the relationship of vehicle speed/gear selection/engine revs. Once you are good at shifting by double de-clutching, you move onto using no clutch. Double de-clutching gives you a 100 or so extra revs either side to get the shift right, without getting stuffed up. Far as I remember when you take a driving test you have to double de-clutch or it's a fail. Also driving instructors will only teach you to double de-clutch, however I may be wrong on this as the only instruction I ever had was " get in the thing and go there". Anyway proper gear jockeys will know more than me. Remember you also have to move between the ranges and if you don't get that right you are in trouble.
The last time I had to take a driving test, I double clutched for a few miles and then asked the inspector if I could do the rest of the test without using a clutch. I was told that since I demonstrated that I could double clutch, it was OK to continue with out using the clutch.
I have always used the clutch just to start and stop, I never had much luck with the clutch shifting threw the gears :Banghead always ended up grinding them til they fit.
I helped a friend get him his class A, and without thinking about it I just taught him to ghost shift. Well, the examiner didn't like it much when he just went straight into clutch-less shifting and failed him.
WOW! Chevy I was worried about that, I got some funny looks last time I took the driving test but I still passed. Maybe I better start practicing for this one.
I had the same thing. I sent a driver down to take the test and he was very good at shifting without the clutch, good clean shifts. The examiner told him she would fail him if he didn't use the clutch. So he did and ground every shift but she thought that was just fine and passed him.
I'm a no-clutch kinda guy myself. Started out in a '63 B-Model Mack with a quad box, that thing was geared so low and so worn out that even with a load on, on level ground, you could have the main in 1st and just gently push the auxilary into underdrive, and it would take off like you let the clutch out. I've had throwout bearings, clutch shafts and other things go wrong over the years and never had to worry about being stranded with the no-clutch deal. I've had to start 'em up in gear loaded a couple times to get the load off and get it home. No big deal once you've had no choice in the matter I guess. Currently, I have a Super 10 speed (which I hate with a passion,) and I tend to shift that by taking it out of gear and "splitting",(not splitting really, but a full gear,) then sliding it back in and repeating the process. Same for downshifting, I use neutral as a substitute for the clutch. Makes a nice, smooth transition. I could never drive a truck smoothly with the clutch, always learned to do it without it, so that's all I know. I've seen some guys who double clutch every single gear, and still manage to pull the front wheels off the ground every cog. I judge a "good driver" :cool2 by his first 2 minutes in the seat. If he doesn't use the clutch brake to stop the countershaft and "click" it into gear, that usually is the end of the judgement right there. If he tucks it in gear by brute force or just grinding against the intertia of the gears till they mesh, he's done as well. Time to downgrade him into something a little less complicated, like an automatic.
I always drive without clutching. I found the best trucks to do this with are old Detroits mated to Road Rangers. I drove several, tow with plows and wings. I could release the brakes at the sand pile after filling the hopper, roll slightly, slide it into 1st and head out. When I got to my roads I'd drop the gear, keep right on going and do my entire route w/o clutching, hills, wing, mailboxes and all. Each of my turn-around points had a place where you could roll slightly, just enough to keep your foot off the clutch. After 20 or 30 hours of dead-end roads, your knee really appreciated not having to hammer on the clutch.
Oh, come on we all know that mailboxes don't make a difference anyways, what would you have to clutch for anyways, they don't slow the truck down enough to make a difference.
No, mailboxes never slowed me up much.
Just a question, but, by grinding against the inertia do you mean rolling the gear until it meshes? I've never heard this referred to as "grinding" and have asked many people who have all said rolling the gear isn't that bad for the truck. I always try to make smooth shifts but sometimes I would assume it happens to the best of us. I'm wondering if there are some differing opinions on this.
Lowboy, I am with you on the super 10s. It is like driving with a 2 speed rear end. I takes all the fun out of driving.
Exactly Bob. My last Pete I got used with a Super 10, and I hated that thing since the first time I engaged the first gear. I ran it for a couple of years and hated it more as time went by. I bought a used 18 from a guy who wrecked his Western Star and set it it the garage corner, awaiting the "Big Bang". Sure enough, one day with a full barge of #2 oil in the tanker, it failed. I celebrated the situation, because I knew it was going to be a great day once I got the 18 in. And it was. After a wrecker bill, another guy to come take my trailer and unload it, and a couple thousand dollars in odds and ends, bits and pieces, I had a normal truck once again with an 18 behind my N-14. That Super 10 was (and IS unfortunately for me for another 2 weeks,) just like a 2 speed rear. I always go into neutral to snap the next higher cog on the button to ensure it goes in, as you know, if you don't wait long enough, it don't go too good. My old one was so slow in going in that many times if I was not completely tuned into my game, I'd snap the button, think I was all set, then a few seconds later realize the tach is wound around to about 5 o'clock and I'm about to be rolling backwards on the interstate. That's a testimony in itself on how tough those N-14's really are right there... 440Chevy, to answer your question, "rolling" a gear to slow it down isn't really damaging as long as there's no KLUNK when it meshes. I was talking about the hotshot who jumps in the seat and grabs hold of the shifter, and stabs it in gear like he's rowing a johnboat. That kind of "rolling" ain't so good.:cool2 That's why a functioning clutch brake and the sense to use it every time you engage the clutch (to take off, not every time if you're a double-clutcher,) is essential to the longevity of all the components in a drivetrain. Stabbing a tranny in gear just eventually wears everything from the tranny itself to U joints, differential parts, etc. A properly functioning clutch brake works by depressing the pedal all the way down to the floor, and feeling the brake as you are applying pressure to the stick simultaneously; there should be an effortless "click" into gear with no grinding at all. You may have to depress and let up slightly while putting stick into gear, but you get the picture, it's an aquired feel. The difference between a decent chauffer and a "jerk", best describes the use or non use of the clutch brake. Ask anyone who owns equipment and pays drivers.
Yeah when I started driving I spent some time at stop signs trying to get it into gear before I knew what the clutch brake did. I was more talking about when your actually shifting gears though. When I was first learning I didn't exactly make smooth shifts and even now I get ahead of myself when I'm on a hill and want to make sure I don't miss it. But anyway it still feels like your rolling the gear when your putting pressure on it before the rpm drops enough for it to mesh.
Yeah buddy! Like your sittin' at a red light, mindin' your own business, with a driver next to you...and you hear that "CLUNK"! Man that makes my skin crawl. And, obviously, that's a driver that ain't got a clue what a clutch brake is! I'll throw something else in here that drives us mechanics absolutely bonckers. A driver brings his rig in for you to do something to it, you get up in the cab to pull it in the shop, put your foot on the clutch, and...no free play! :Banghead The clown didn't even mention "...and while your in there, I need my clutch adjusted." If you don't know how to use a clutch brake, or know that the clutch pedal MUST have free play...you ain't no truck driver. :drinkup
Ditto:thumbsup (hope that's OK to say)
I had a water truck driver who had been doing it for years before I hired him. He was a pretty good hand, but I did not realize he did not know about the clutch brake. He got it right putting it into gear each time, no growling, so I thought he was OK. Problem was he was a clutch shift type, and he pushed the pedal ALL the way each shift. A few months went by and he tells me " I don't know whats wrong, but I can barely get the truck into gear anymore. Its fine when I am mooving, but when I am parked, I have to shut the engine off to get it in gear" I told him the clutch brake was worn out, and he gave me a dumb look and said "Whats that?" Driver education started after that. He told me in 12 years, no one ever told him about a clutch brake.
Good point, I'd say it happens quite freqently that a lot of drivers were "never told about it". And when you hire on a driver, your not going to ask him "do ya' know what the clutch brake is?" But doesn't this go back to the original teacher? After all, all of us learned from someone. I just don't think it's the norm that a person just stands beside a truck one day and says to themself "I'm going to get in that truck and drive it". I'd say it's more the norm that we get up in the cab and someone "shows us" how to drive it. That's the person, if they're a true truck driver, that should have taught their student about the clutch brake, clutch free play, checking brake adjustments at the slack adjusters, all the little things that a true truck driver should know.
And I get tired of suggesting to the Boss man that he needs to ask "can you drive?, instead of "do you have a license?"
Yes, but they all THINK they can drive. You do not really know untill you see them do it for a while. Even then, some things can slip by.
Why would you be failed for clutchless shifting? Is this a safety issue?
Not at all. The examiners have no personal knowledge, only what they have been taught by someone who also knows only what is in the book. Anything outside that is not allowed and of course they instantly become defensive if anyone questions their lack of knowledge. I had another driver who was absolutely prevented from taking the driving test because he could not demonstrate how to adjust the brakes. That particular truck had self adjusting air brakes with no provision for adjustment at all. No amount of talking would even induce the examiner to look at the backing plates.
When I tested for my A license, I asked the tester, and was told that if you are shifting without the clutch, you may miss a gear, or be "out of control of your vehicle". I was thinking that you are just as likely to have something like that happen with the clutch as without, but I kept my opinion to myself, and proceeded to grind gears with the clutch. I had driven for years without a clutch, so to suddenly use it to take the drivers test, threw me out of rythem. They even wanted the clutch used for range and splitter shifts. Once I was aware of that, I took the whole test without a range shift, just so I would not forget to use the clutch.
Since we are a little off topic I can't resist making a coment on examiners. I was required to get my CDL not to long ago ( thanks smokey bear ) after 12 years or more on the road. Yes this was very naughty of my and I apologize to you fellas who got yours when you were supose too. I found it kinda difficult at times to follow the proper way to drive acording to the dot. Meaning the clutching, no shifting threw intersections and so on. I had all these habits from driving that they didn't like. My instructor thankfully was pretty cool and acepted my logic in the things I did. On the way to take my test I took a friend to get his cdl as well and we tried the no shift threw the intersection and got passed by a state pickup truck ( needless to say he passed us using a turn lane in the intersection ). Did the parallel park thing between the cones and was within a half inch of the line rather quickly as it was nothing compared to my normal daily driving routine around houses and utlities. I got the lecture for that one as I was told i hit a building ! I bowed up on that one. I wasn't told the line was a wall before I backed in there. And in my 12 years of driving I've only dinged 2 things other than water meter boxes. Both were pickup truck in a narrow subdivision in the same week. The first one I just cliped a mirror. The second I almost made it didn't alow for the front wheel studs sticking out and swirl marked a brand new chevy 1500. Amazing the damage a wheel stud can do !!! Wanted pics of that one but thought it a bad idea with the drive jumping up and down throwing paint cans and teaching me a hole lot of new four letter words along with the lecture that he was only gonna be there 5 minutes so I should have waited for him. He didn't like my reply of maybe he should park next to the curb when the streets are narrow instead of 2 foot away from it. When all I needed was another 1/2 inch and he would have never had a scratch. I wasn't so lucky as some with the training in that all mine has been the keys are in it. Get it done. From trucks, dozers, hoes, and skidsteers, ect. So I probably have a couple of bad habits and still learn new tricks all the time from watching others and always will. to answer the original question I've always shifted without the clutch in large trucks. A lot of the ease in it is the lower rpms of the diesel engines. Had a clutch slave cylinder go out on a f250 diesel of mine once and had to clutchless shift and starter takeoff in it to get it home for repair. The syncros are normally made of brass in the smaller gear boxes and easlily prone to damage.
imo a clutch is there for starting and stopping. I never use it for shifting however I think its better to shift with it then grind them. Use it if you have to but dont if you dont need it.
Yair...I reckon that pretty much sums it jdman04. I only ever drove two stick Macks. Running loose you sucked them through and other times you clutched them. On the compound shifts on a quad box I always used the clutch. There used to be a stretch of gravel road west of the little town of Injune in Queensland's central highlands where hauiling a scrub equipped D9g and about 10 tons of chain with 211 horse-power and a quad-box there were 387 gearchanges in twenty miles, you just could'nt do it without the clutch.
you can do it but dont but the jake on its really hard and dont shift at low rpms
Yair...Case 580e, no jake.... or any other kind of brake much as well as I remember. No choice much with RPM with that weight and HP. We were running 32mph diffs...on the way up you maxed it out and on the way down you changed when you freaking had to.
i used to always try to shift with the jake because it was stright piped its sounded good untill i didnt use the clutch
I'm sorry I gotta know, What's a "Scrub"? Tah, Mate! I owe you a XXXX!
This may be a dumb question, but how do you split a downshift without clutching, or can you?
Let's see if I got you right; your pulling a grade that's making you drop gears. Your in the low hole, and you need to make a lower range shift and take the stick to a high hole. Right? In this case, when you pull the shifter into the neutral position to make the change from low hole to high hole, and select a range shift at the same time; the range shift is going to be made regardless of clutch because the stick is in the neutral position. But an experienced driver will prefer to have the clutch engaged during this neutral period so he can control engine rpm with throttle pedal to allow gear alingnment, the tranny makes the range select change long before we hit the gear.
Yair...Guday Muffler Bearing, I'd love to get over there and take you up on the offer of a xxxx! User name refers to the fact I spent a great deal of my seat time clearing land or "scrub pulling" in Queensland. Millions of acres were chained down from the 'fifty's right through to the eighty's...and now it's illegal. If anyone is interested in gear and techniques I could start a thread. Don't have many pictures (lost them in a flood in 1974) but maybe I could get some if there is any interest.
I should have been more clear myself. I get what you are saying, but I'll start over. Say you are driving a 13 speed and you are in 13th "gear." How do you get to 12th? Id imagine that you'd have to slide the splitter button back. Do you just give it some pedal to take to load off of the transmission and it will shift? I understand downshifting a full gear, but I wasn't sure if you could make downshifts with the splitter. Im just curious, the dump truck I may get to drive has an 8LL so I dont have to worry about it too much right now.
Man it's been too many years since I've driven these tranny's. Sounds like your talking about one of the old RTO's that 12 is the 5 hole/HI range, and to get thirteen you select OD range. I drove an old Link Belt with a tranny like that and didn't much like it. To drop from 13 to 12, you pulled the selector back to HI range. You can make that split up or down without the clutch, it's still all in the throttle foot. Make the select under load, then relieve the load by letting off the throttle, it will come out of the OD gear. Then you throttle it back up to the proper rpm, and she drops right in there. This still requires the same skill as shifting the lever/gears without the clutch, you have to have perfected the knack of operating the throttle properly, not over or under revving engine during the shifts, your throttle foot has to take the engine right to the required rpm to mesh the gears.
I usually just bring it out to neutral, drop the button back, rev it up, and slide it back into gear.
Yeah, 440chevy, that's what I had to do with that Link Belt I used to drive. It was an RTO513...613...heck, I don't remember. It weighed 77,000 and had a 6-71 Detroit, needed every gear to get it down the road. Three gears in the LOW range, then 5 in the HI range spliting OD in each of the 5 HI gears. It would make every HI/OD split perfect...but 12 to 13 missed everytime. Had to pull the lever out of the 5 hole into neutral of HI 12, select OD, then back into the 5 hole for OD/13. Everytime! :beatsme
Thanks that cleared it up guys. Im sorry to hijack, but I guess it was kind of on topic.
well i guess im still a little confused! some of you guys clutch, yet others just feel the gears!as i said, ive only drivin cars and light trucks, doin the no clutch thing! just wanta know whats best!!!
From what I gather its personal preference. Double clutching gives you a little more time to make the shift. If you can shift without the clutch, do it. No need to wear out your left leg and your clutch. Disclaimer- I am not experienced and haven't ever driven a heavy truck either, so my opinion is based on my decent understanding of how transmissions work.
I think ATCO is right, the one thing I have noticed driving is, to me, double clutching is more of a timing procedure than actually using the clutch to work. What I mean by that is it allows the rpms to fall down to where the transmission will shift right in. When I am driving a new truck, or if I get in a bind or out of synch I will double clutch, but I have noticed that I am not actually engaging the clutch I really just take the free play out. I have also noticed that when I ride with our drivers, everyone has a different style, some will run the rpms up more than I would or some will shift quicker than I would, as long as it works, the transmission shifts, the driveline does not clunk and the truck moves down the road then however it got to that point that it works is right.
The way I see it is it doesn't matter what you do as long as shafts in the transmission match speeds. The only benefit I could see from double clutching would be a little more time to make the shift, if thats really a benefit. Im not sure if its been said already, but I would think with the clutch engaged the input shaft on the transmission would slow down faster with the engine. I know those shafts arent light, so by disengaging the clutch during a shift they would "freewheel" a little longer and give you more time to grab the next gear.
JFortner5, your right in the middle of understanding this. This "clutch or no clutch" thread has become one crazy and informative thread talking about something we do all day long with out giving much thought to it. As Red Bank stated; "as long as it works". I thought I'd throw a post in here for anyone who has never driven a heavy truck transmission to try and explain, partly, why we do what we do shifting these things. Aside from getting tired of mashing the clutch pedal all day :Banghead, maybe part of the reason we all learned to shift by leaving the clutch engaged (no clutch) is because of a simple principle of physics...inertia. JFortner5 has figured this out. Unlike a car tranny, the gears and shafts in a truck transmission are large, and their mass creates a "flyweel effect" of the moving parts, which is where inertia comes in, the law of physics that says that anything in motion will remain at it's current speed until it encounters an external force. To keep things simple, we won't include the friction of bearings and gears meshing, just a basic overview of how inertia affects shifting a truck tranny. Let's say your in a loaded truck, and you run a gear until the engine is on the governor. It's time to shift to the next gear. At that point, if you just pushed in the clutch and tried to shift to the next gear, you'd get nothing but grinding of gears. That's because the gears/shafts are subject to inertia, they'll keep turning at their current speed until some external force slows them down to engage the next gear ratio. Thankfully, we have an external force that we have control of...the engine. But in order for us to use the controlling force of the engine, it has to be coupled to the transmission...the clutch. Here's how it works; rev the gear to the engine governor, don't mess with the clutch pedal, pull the tranny in neutral, then let off the throttle. The engine is now coupled with the tranny. The engine rpm drops quickly when you let off the throttle pedal and, likewise, quickly slows the turning of the tranny shafts, which then allows you to mesh the gears. At this point, JFortner, that's where the double clutch comes in. The double clutch is this; rev the gear, push in the clutch to pull lever into neutral, then clutch out to let the engine slow down the tranny, and at just the right rpm, push in the clutch to mesh the gear. It's not long before you get the feel of things and you just forget the clutch altogether and control the shifting using nothing but the throttle pedal. And your left leg thanks you.
I really want to try and drive one. I think I've got the basics, I just want to try and actually do it.
As long as you remember to pull it out of gear while your still accelerating the rest isn't to bad pending some grinding. I got my truck last October and I parked my pickup and bobtailed everywhere for about 2 weeks and just had a blast. I had been driving a dump truck with an Allison for 3 years by then so the size never bothered me, which helped. As far as the clutch issues, most people I talk to just do whatever they feel like doing, which is the same for me. When I'm pulling a steep hill with my 13 spd I just feel like double clutching helps when I'm going through 1-4, but when I get into hi range with the splits I don't find it necessary anymore. I definitely think that one should be able to both efficiently.
Which brings us to the next section of the class:drinkup Changing gears when loaded and empty, or when bobtailing or pulling a trailer, as Atco pointed out above the weight of the load will also weigh into the inertia equation. I think the hardest thing to learn for me was to shift without grinding when I was bobtailing a tractor. When I am loaded I feel like it is a whole lot easier to shift, whether using the clutch or not.
Yair...dunno about the modern trannys but don't quite agree there ATCOEQUIP when you say "pull the tranny into neutral, then let off the throttle..." on the old two stick Macks and Fodens and what all it was all kinda one action, you had to let off the throttle in order to take the load off the gears so you COULD pull the stick into neutral. Does that make sense to you? Difficult to describe this stuff per medium of just words, you are doing pretty good I reckon.
You darn skippy, Srub Puller, it is a bit difficult to put this stuff into words. I guess I'm doing it because I find it to be an entertaining challenge. Like I said, this is stuff we do all day long and don't give it a thought. It's a little tougher tryin' to 'splain it in writing. I guess that one description got a little vague. I was trying to describe an upshift, your absolutely right about letting off the throttle enough to relieve the pressure on the gears is the first part of the process, then the part I was trying to explain is "you pull it in neutral and let the throttle off so the engine revs go down to the proper rpm for meshing the next gear." When it get's there, drop it in gear, and throttle back on. That's what I was trying to say. I'll keep working on it.
are you guys tellin me, the over the road guys just find the gears, but dont need to clutch?
Naw, never said we don't "need" the clutch, just in many circumstances we don't "use" the clutch. You just do whatever works best for ya'.
I would think one could safely say most truck drivers only use the clutch when starting out. Other than that it's all about using the gas pedal to shift.
Then we can move on to advanced shifting techniques (without the clutch of course). For instance when bobtailing or driving without a load, there is no need to use all the gears. That is when you skip shift. When my dumptruck is empty I only use 4 or 5 gears depending upon circumstances. When doing this, you have to wait longer for the gears to slow down to match rpms since you are skipping gears. If going down hill, you may be able to skip several gears at a time. Another "advanced" technique is when pulling a heavy load up a hill in the lower gears - 1st to 2nd or 2nd to 3rd or even 3rd to 4th. What happens during normal shifting is that the truck speed slows quicker than that big ole engine can wind down so you can't make the shift. There are 2 solutions. One is to use the engine brake to slow the engine quicker (burp shifting), which if done wrong can damage u-joints. The second, and the one I prefer, is turning on the fan with the manual switch. The fan helps to slow down the engine quicker. I find in most cases, if I don't rev the engine up too high, the fan does the trick just fine - I guess I would call it short shifting with the fan. These are things that can be learned once a driver has the timing down on regular shifting. For those that enjoy driving trucks, this just adds to the fun factor.
I've heard of burp shifting but no one ever told me what happens when it goes wrong. Haven't heard of using the fan, I'm looking forward to trying that trick out. Thanks.
keep the education comming guys! im sure im not the only moron here ,to want to know how you pro-drivers do every day!
Yair... it's a different world you blokes live in....and I can't tell you how much I enjoy these forums. Please excuse my ignorance Bob Horrell but do you mean turning on the "manual switch" of a thermostaticaly controlled electric or hydraulic engine cooling fan? If so I would be curious as to the ambient temperatures in your area and what percentage of the time the fan actualy runs. What is the operating rev range of the modern truck engine as I am having difficulty coming to grips with some of the techniques. As mentioned in other posts I mostly drove two stick Macks...from 6-71engined NR's to a variety of "B" Models, the ones with the triplex box were best for our normal bush road work. None of them would lug and you had to keep them on the boil...a usable rev range of about three hundred kept you busy on the sticks.
Scrub Puller, actually the first big truck I ever drove many years ago was a twin stick. It was in the Mountains in Colorado. You had to learn real quick with the steep and winding mountain roads. I probably couldn't do near as well today with a twin stick. It has been a long time. Yes, I was talking about the engine fan. I have an extra large radiator and engine fan. The fan really slows down the engine quick. The summer temps. where I live average mid 90degrees farenheit to above 100. I drive in a very hilly area. My fan only comes on automatically on hills or if I am going real slow on a dirt road. Of course the more the load, the quicker the fan will come on. My truck has a 500HP Detroit Diesel. Max rpm is just over 2,000 rpms with the max torque at 1500 rpms. Detroit spec sheet says max fuel mileage is at 1400 rpms.
Yair...thanks Bob Horrell, some of the operating techniques and comments are starting to come together in my head. It's a different scene completely with a usable rev. range between 1400 and 2000. I appreciate the comments and explanations as I am about thirty years behind present technology. Some things never change though and your use of the engine fan is somewhat analagous of the way we used to go up and down through the boxes of the six speed Allis Chalmers HD 16's when towing cable operated scrapers....i.e. a quik tap on the winch lever would slow the gearbox down to make the shift. It took a bit of getting used to...double de-clutching with a hand clutch and a decelerator. We did'nt hafta do it of course but we were young and sappy then and did it 'cause we could
great trick with the fan, I fight to keep those things cycling properly, it's sad how many drivers have no idea if their fan is cycling or just running constant.
Just to chime in on skipping gears a dairy truck driver told me about his Technique for leaving dairy's loaded at the wee hours of the morning he would get rolling 1st, 2nd ,3rd then let the Jakes hit hard and go from 3rd to 6th when the milk sloshed in the unbaffled tanks.
To me the engine has a "sweet spot" where when shifting at that RPM the gears just fall right in! With Cat it's 1600 to 1700 RPM! Cummins is 1800 to 1900 RPM. The 2 stroke DD was max throttle, while the 4 stroke DD was like the Cummins. Mack seem to **** the best for me at 1800 to 2000 RPM! And this is with the 8LL, 10, 12, 13, 15, 18, 20 speed RR trany! Like you there Bob H. I only use the clutch to start! I bump to N to stop. I have NEVER had a clutch burn up, or damaged a transmission, or a PM'ed U-joint I have tore up dry U-joint, and I twisted the yoke off a drive shaft once, but the shaft was cracked and the was only 1 inch the was a fresh break, the rest of the crack was rusted! Drove my Ford to a job sight last year and felt a different vibration. Thought I was just super sensitive that morning, as I hauled a couple of loads and pulling out with one I felt the vibration get worse, so I checked and the carrier bearing was no longer mounted! Stupidvisor wanted me to keep going, and I told him that I would call the truck boss and check with him! I was asked if I could bring it in. I told the man, I drove it here, if I have to push it back I'll get her there!
That sounds about right Driving milk trucks are a complete different animal
Yair....road's straight and flat to the horizon, looks flat but it's not, your running at about130,000 pounds with a 6-71 up front with five in the main and a two speed splitter, your in third low and she's whistlin' Dixie on the governor and you just KNOW she'll take it half a gear higher, gonna try that one without the clutch?
NOPE! I I'm too rusty on twin stick shifts, and to shift both sticks at once requires a lot of pratice! Even with pratice, that is about an impossible shift! You'll loose to many RPMs shifting both sticks. You'd loose 2 or maybe 3 gears getting that shift without fouling it up! If I were cresting the mini hill, I'd stay in her to 2150 then take the full shift! If I was at the bottom, I'd let her lug down and drop a full gear! Been there done that! BTW that was a trick question!
Yair...no trick question rino, next shift's into third high in the joey box, just asking if anyone's gonna try it without the clutch?
Oh yea, I'd do it no clutch for sure. Off throttle, snick the box and back on. The bad place to be would be third high, then you're in ugly territory. The Detroit is so unforgiving if you wait to long in the shift, they like their RPM's, the two stick shift and all that weight makes it fun. Instead of " looking" flat though, make it a hill, a steep hill, like maybe you might be going the wrong direction when you get the shift done. That's when that shift is spooky, if you miss, you better hope you catch a lower one before you stop, on a steep hill/mountainside, if you let it stop all the way with a lot of weight, the clutch/ drivelines and ujoints may not let you get started again. I let a little 3208 cat with a 13 speed get the better of me one day like that. Started up the hill (think long little mountain lane out of a jobsite), in a hurry, I thought "she'll take one more gear", so I shifted. Yeah, I was talking to that Cat, "come on baby!" The little cat replied "unngggghh" in a slowwwinngg tone. Nope, she can't make it. Yep, I was stopped in the middle of the hill. Ten guys back at the cabin looking up the hill at me stopped. Yep, I've got no pride, I rolled back down it to the flat, and started all over again. This time I left it in the bottom hole all the way to the top.
Hi, This has been real enjoyable guys. To shift the old 2 stacker DW 20s & 21s you had to have the RPM pretty close to right or take the shift lever in your right hand and grab the hoist lever by reaching across your right shoulder with your left hand and dog the unit in and it would fall in gear. That was for from first to second and second to third. From there on up anything worked.
clutch or no clutch: Said the same words, only I usually add two stretched out "pleases" after baby. The first please has a definite begging tone... (still a glimmer of hope) The second please usually has a full begging/sobbing/whining tone... LOL (hope is now in the past, but don't give up) Heard that too, but I couldn't have figured out how to put it in words like you did... :thumbsup... LOL And, of course, if there is a third please, it has nothing to do with talking to the engine... That was a good post crane operator... OCR
Over the years , I have seen some horrible shifts . I have also been inside some traumatised transmissions . A little bit of a timing error with a clutchless shift can explode a transmission . A gear/dog not fully in mesh will jump back out with a huge bang , either on acceleration or retardation . The young guys I taught to drive were told , if the truck is pulling hard up a hill , use the clutch to upshift . If it's running along quite easily and keeping it's momentum , float the gear .
Yair...good one Iron Horse my thoughts exactly. (With all due respect) I reckon some of the fellers here are a bit precious about this clutch or no clutch deal. Once upon a time the scenario I mentioned on page six of this thread was a pretty common situation for me. A Nine G with half a scrub chain weighed the same then as it does now...only we had about a third of the horse power to pull it and on dead roads with a 32 MPH back end there was not much in the way of momentum. I always found the clutch gave a little leeway on those "desperation" changes...if you blew the shift you could be back ringing the hi-lo back and forth in second for maybe thirty miles. There's some good posts here on this thread, keep them coming fellers it realy makes the day.
I pre-select the splitter button, wait for a bit to make sure, lift my throttle a touch to get it into neutral and then give the throttle a little blip (200rpm) and then once I'm sure it's properly engaged it's hard back on the gas.