[jonp]

Originally Posted by Windwalker

Well, as a seasoned driver, I do know how to float the gears. However, I've only done so one time. The pin that is the pivot point for the clutch peddle broke in a KW T-2000. In order to get it to the dealer to have it fixed, I had to shut down the truck at a red light, then start it in gear and float the gears when the light turned green.

I DO double-clutch every gear for one reason. I've driven quite a number of trucks that had "notches" in the gears of the transmission. The truck had been driven without the gears fully meshed. Part of it wore and the rest did not. Even had one that broke teeth out of it. When they took it apart, the mating parts were worn not fully meshed. They wear faster, and fail sooner. About a year, or so, before I bought my own truck, two of us were given brand new trucks. We had to watch the temp guages on transmissions and rears until they broke in. Within 2 years, his tranny failed. When they took it apart, he'd been running with the gears less than half meshed. They are not designed for that. And, with the little I've done by way of floating the gears, I find that it is very easy to apply throttle without having the gears fully engaged. Once it starts to wear at that point, it becomes harder and harder to get it completely in gear.

So, if I had a fleet of trucks, and found out that you are floating the gears, I believe I'd find a reason to let you go. Floating the gears just makes you a BBR.

Good post. Thats also why I don't float often. We slip seat the trucks and believe me they are used trucks that come to us from the national fleet with 4 or 500,000 on them and the miles have not been easy. Double clutching the truck all of the time is the only way to find the gears on some of these trucks. When I took a new guy out last week he amazingly asked me if I knew how to float when I double clutched. I floated up and down the gears and said yes but then told him why I never did it.

Its way too easy to miss a gear in a hard-used truck and an out of gear truck is an out of control truck.

[Scooby_1970]

O.K I know I am new here and getting ready to go to school, but why do you have to double clutch? I am just trying to learn here what I don’t know. I have driven with a clutch all my life and have always just pushed in the clutch switched gears and then released the clutch. Why can’t you do the same in a truck?

[Roadhog]

Originally Posted by Scooby_1970

.... why do you have to double clutch?

To keep this simple, double clutching is used on an unsynchronized manual transmissions. Without synchromesh, you have to mesh the gears yourself. The entire point is to match flywheel speed, input shaft speed and output shaft speed, reducing stress on all the components of the gearbox, and stop power being lost as heat in the clutch.

You are basically doing two shifts, with each gear change. Clutch-move to neutral/clutch move to next gear. If you are downshifting, you will also tap the fuel pedal to increase the rpm to your shift point. You will learn about watching your rpm's while making your shifts. To begin with you are just going to get the basics down. Your clutching is like a half-pedal motion. It is done quick and smooth with gear changes in concert. When done right, it is a fast smooth process. (I'm going to let your instructor beat the basics into you)

There is a clutchbrake towards the end of clutch travel. This stops the gears from turning so they can mesh at a standstill. You only clutch this deep to engage the clutchbrake, when you are stopped, or you will wear the clutchbrake out. I've driven plenty of trucks with a worn out clutchbrake. If you are stopped, and have a worn out clutchbrake, the gears just spin, and you can't engage a low gear. What I do then is clutch, slip into a high gear which will slow the gears down, then quickly into the gear I need before the gears start to speed up again.

You also learn about progressive shifting. You want to slip through the gears with less engine noise and get the truck up to speed quicker. Running the engine up to peak rpm in every gear wastes fuel and makes more engine noise. You also have more torque at lower rpm's. Progressive shifting saves fuel and equipment wear. The idea is to let more of the transmission do the work, and less of the engine. This takes stress out of the whole driveline. Transmissions shift on a percent of engine rpm, and you actually put the gears closer together when you upshift as early as possible. That spends less time in neutral and more time pulling the load.

It's easy to confuse a new driver in the beginning, so for now just plan to get the basics down, and build your foundation. These transmissions react differently bobtailing, pulling an empty trailer, to various weight loads. Also shifting is much different on flat land vs. hills, or starting out on steep grades. You will adapt to all of this, if you really learn the basics well. The basics is also what you draw on in emergencies, as your foundation becomes your instinct.

Your learniing process will be like progressive shifting. You will learn allot fast in the beginning, and go to the next step quickly. The process slows down with more space inbetween as you gain skills and experiance. A good driver is always learning something new, so keep this in mind when you start out. You are beginning a learning experience that will go on throughout your career. Take things a step at a time, and those first steps are important to learn right, so don't be sloppy. A sloppy driver will not learn skills, as much as bad habits.

[GMAN]

Whether you float the gears or double clutch, the idea is to shift without scraping the gears. You should NEVER force a truck into gear. Doing so could damage your transmission. If you get your rpm's at the right level you should be able to easily shift into the next gear.

[Jackrabbit379]

I tried using the clutch. I think I had worse luck doing that than not using it. :eek2:
You want to be easy, and don't try to cram it in the next gear. There is a window that opens when you take it out of gear. It stays open long enough to slide it in the next. Someone told me years ago- you take it out of gear, and count 1 second, and slide it in the next. Obviously, it's easier to say, than do. I've noticed over the years that all trucks sing a different tune.
If you watch the tachometer, you might try not to use it. I tried it, and it drove me nuts. I tried to take it out at a certain rpm, and when it dropped to a certain point, I tried to put in the next. Never worked. When it was time to shift, I took it out of gear, and acted like I was pushing in the clutch and slid it in the next gear. I very seldom look at my tachometer.

[Hawkjr]

sorry my trucking dictionary is kinda of lacking but is floating shifting gears without using a clutch?? if so i'm guilty as charged.. when i started to shift without the clutch my leg at the end of my 14 or whatever use to feel alot better then when i was double shifting.. like GMAN said if you can shift without scraping gears then your good!!!

[Roadhog]

I think you guy's keep missing the point here.
Any seasoned driver can float gears. :roll:

This is the new driver forum, and someone seeking advice in the basics.

Most states will require double clutching when taking the CDL Skills test, as will most companies expect
their prospective drivers to demonstrate that they know how to double clutch during their company road tests.

[jonp]

Originally Posted by Jackrabbit379

I tried using the clutch. I think I had worse luck doing that than not using it. :eek2:
You want to be easy, and don't try to cram it in the next gear. There is a window that opens when you take it out of gear. It stays open long enough to slide it in the next. Someone told me years ago- you take it out of gear, and count 1 second, and slide it in the next. Obviously, it's easier to say, than do. I've noticed over the years that all trucks sing a different tune.
If you watch the tachometer, you might try not to use it. I tried it, and it drove me nuts. I tried to take it out at a certain rpm, and when it dropped to a certain point, I tried to put in the next. Never worked. When it was time to shift, I took it out of gear, and acted like I was pushing in the clutch and slid it in the next gear. I very seldom look at my tachometer.

yeah but your an icon! when i float i will look at the tack but mostly just wait a sec and ease it and it goes. I still double clutch just about all of the time

[firebird_1252]

the best advice i can give is.. once you learn the style of shifting you'll be using and what speed is what gear.. just dont think about it.. its natural.

[GMAN]

You will learn to shift by checking your rpm's. Once you gain some experience you will likely not check your tach much. It will be more a matter of the sound of your engine. I rarely look at my tachometer.