Question about manual transmission differences

The clutch brake on a truck is engaged all the way until the clutch pedal stops.

As in a car when shifting, in a truck you push the clutch in until it completely disengages and you go into the next gear - you don't have to slam it down to the floor board in either a car or a truck. You can do this just like a car, you don't have to float it in, floating is done without a clutch. A car you don't have to double shift but I own cars where you do, they have non-synchro boxes just like a truck.

When I was driving, I would either float the gears or use a single clutch move to move through the gears, which wasn't hard to do and it was like driving a car.

The issue is getting the coordination between your hands, feet and head together so your uncle and others are wrong about learning it at school. Driving a car with a manual is the best way to learn how to drive a truck because once you get used to driving something that isn't going to be hard to learn (basic four speed) then you can learn the truck.

The other thing is that it is not hard to learn how to adapt to the different trucks and shifting patterns, that is just practice and moving one part of your body, there are no unique or odd patterns in truck transmissions, the same basic pattern is used on all of them, H or a modified H pattern with the lowest gear always to the left.

 

The clutch brake only applies only in the last part of the pedal travel.

In a truck if the RPM's don't match it won't go into gear no matter what you do with the clutch.

 

I know, but others seem not to.

I have road tested guys with 5/10 years of road experience who have slammed down the clutch pedal to the floor when shifting every gear as if it was a race. I know they hit the clutch brake every time because they had no issues with getting into a gear every time.

When I was driving, the only time I would use the clutch brake was when I had to come to a complete stop without being able to downshift into my staring gear or reverse.

you hunt the gear, move the rpms up (or down) a little bit until you 'feel' the gears getting close to equal speed, it can be done without a lot of practice. BUT it takes practice.

 

Sometimes pictures help so here goes....

A modern 4 wheeler or dually pickup or most medium duty trucks, use a clutch that is "pressed" when you shove the clutch pedal down.
Not so with a Class 8 such as your going to be tested in. On a class 7 or 8 road tractor you will find a clutch that is "pulled" when you shove the clutch pedal down.
I use the term "pulled" because of the movement of the throwout bearing... notice picture where I have my finger on the throw out bearing...
When you push the clutch pedal down, the clutch fork will actually "pull" the throw out bearing backwards towards the transmission. A car or pickup "pushes" the throw out bearing forward toward the engine.
Now, keep in mind when you push the clutch pedal down most of that travel is operating the pressure plate, which the throw out bearing is attached to (notice pic with my finger again).
After the throw out bearing travels so far and the clutch pedal nears the floorboard, the throwout bearing actually starts "pinching" the clutch brake... (see pic with clutch brake on the input shaft)...
The clutch brake is about is about 3 1/2" or 4" in diameter. When you shove the clutch pedal down all the way and pinch the clutch brake, it slows and stops the input shaft of the transmission. This is why many have posted DON'T shove the clutch all the way down, when shifting from one gear to another. Shifting in a big truck is all about timing and rpm's in a sense, the input shaft of the transmission needs to match the rpm's required for the next gear, no matter if it's a higher gear or lower gear. I myself just listen and feel when I shift, after 30 years it's 2nd nature lol. Notice also the 2 clutch plates in the one picture with my finger, twin disc clutches are common in larger vehicles, sorry the spacer plate that goes between the 2 clutches is not there.
When you get ready to do your driving test, you should be able to shove the clutch against the floorboard and the transmission go right into gear ( IF the clutch brake is adjusted properly). Getting the truck into gear ready to start moving, is the only time you should have that pedal on the floor!! When you start shifting between gears you only need to shove the pedal down a few inches to 1/2 way, if you shove it all the way down.... you bump that clutch brake and guess what??? You just slowed the input shaft way down and your grinding gears! At that point you need to let the clutch out stab the throttle and shove the pedal back down...JUST A LITTLE....
You control the rpm's of the input shaft with the engine, and the clutch. In other words, no need of giving the engine fuel to speed up the input of the trans when the clutch is open.
When you take off there should be no reason to give the engine fuel, not until the clutch pedal is up and you are rolling.
When you are ready for the next higher gear, shove the clutch down just a couple inches to 1/2 way, move the shifter into neutral and let the pedal up, at the same time be aligning the shifter for the next gear, shove the pedal back down a few inches or 1/2 way and put the transmission into gear. Remember what I sad about timing?? You only have have so much time to make all this happen before the input shaft of the transmission is turning to slow. Then your grinding gears.
It will take a little time, but don't get all frustrated. I hope there is something in my ramblings that you can use. Be safe out there.

 

I am the exception. I double clutched always. I do float now and then when I need a fast gear and have the ability to do so no problem. But that does not mean I should.

There is one thing I should have a student who has not yet touched a big truck that needs to remember if anything. Any time you are turning out of a side street into a roadway with traffic coming at you... never come out of the gear you are in until you are straight and accelerating. Because there is a great pressure on your 5th wheel that can literally stall you particularly if you are turning into a upgrade or coming off a essentially vertical drop behind your stop sign with the trailer still hanging on it.

 

Try to use your tach, you will see there is a hard torque rating and a top horse rating before redline, around 1250 to 1550 on a detriot if it's big enough. You will see how it also behaves too during upshifting, when it's time to upshift, that tractor is sort of pulling it's ### off you will know it.

There are too many engines and transmission differences to get into, but most modern trucks shift around 500 rpm between gears for progressive or straight shifting charts. Anything older than 1995 and much higher redlines say 2300 have shift points that are very high. Don't worry about those.

 

^^^^^^^^^Ignore all of this^^^^^^^^^^