Double clutching

[Brocky]

I have found it is easier to shift without the clutch with the old mechanical engines, especially at higher speeds, than the new electronic ones. Like Larry I do it by ear and feel and with the electronics you just do not feel the pump with your right toe.

brocky

[lucerne tractor]

 

Our old RD floats nice, partially because it doesn't have a Jake, but the powerleash in the mp7 is too fast for me to beat into gear. Nice forgetting going upa grade with a good load on, but that's it. Nice, smooth, even pull with the clutch

 

I just touch the clutch pedal when I shift to stop the engine brake. In town, empty, truck stops or flat landing I usally shut it off untill needed. Got to love the empty trucks running around truck stops using the engine brake at every shift. Like they don't drive fast enough in them now, they have to speed shift.

[jackb61sx]

When I learned to drive many years ago, my father always said clutch for stopping and starting and after you miss the shifts you learn. Since those days have driven mostly mack's and all with out a clutch especialy the B-61 with the quad and our R Model and DM I drove for another guy. I purchased my 89 Superliner in December with a Cat and 8LL and can shift it with out clutch but shifts faster and smother double clutching, so now I am double clutching and runs fine don't think about it anymore.

[doubleclutchinweasel]

How often do you guys double clutch? I found that its very useful for climbing a hill and getting in the gear quickly to get torque going again quicker. Is it a good practice to do this all day long when loaded or just when you feel you need it? My dad was saying thats how we were taught back in the day to shift and there is nothing wrong with it as long as you are not slipping it. So this is how i do it. I go to around 1600 1700 and just as i get it out of gear i put the clutch about 50 - 70 percent down and it goes right in ( most of the time) and its a smooth transition. Is this how you all do it? Or do you have any tips? Will this wear out the clutch faster and require the clutch to be adjusted more frequently and should be avoided or is it just fine to do as long as you do it right?

Some good responses on this. But, some of them may not address your question!

Clearly, there are two ways to shift; clutchless and double-clutch. Both work fine...IF PROPERLY EXECUTED. You CAN upshift with a "single clutch", as long as you wait for the input shaft to slow down to "match up" the RPM and let it slide in without too much mismatch. But, you CAN NOT downshift without either double clutching or "floating" the shift, because you simply HAVE TO raise the input shaft RPM to the point where the the shift will engage.

Like most of these responses, I typically do not use the clutch to shift when things are nice and pleasant with the world. But, on occasions where I need to get out-&-in quickly, I'll use the clutch to get on with it.

You mentioned the partial depression of the clutch in the original post. Yes, I have been known to do that too! The main point when shifting, either with or without the clutch, is to UNLOAD the transmission to allow it to come out of gear easily...and not chip corners off the dogs! Then do the same thing going into the next one. Sometimes, that little partial de-clutch is enough to do that. Sometimes, a particular tranny will shift BETTER with a partial de-clutch than with the pedal all the way to the floor. Keeps things spinning, I guess.

Used to drive a Mack 18-speed Quadruplex which always shifted easier without the clutch than with...especially on those split-shifted downshifts! Kept you from getting hung-up between gears as much. Now, that's fun...trying to match up both ends of the box to get SOMETHING back in gear...while going uphill...loaded...and losing speed...before the silly thing came to a complete stop. I'm sure there are a few other old-timers out there who have experienced that particular little slice of heaven!!!

[rsb502]

I have found it is easier to shift without the clutch with the old mechanical engines, especially at higher speeds, than the new electronic ones. Like Larry I do it by ear and feel and with the electronics you just do not feel the pump with your right toe.

brocky

+1 for the feel, I push the clutch about half way to kick a trans out of gear to downshift if I have pressure on the shifter other than that just feel the truck.

[e9500v8]

As I was once told you have to have a tachometer ear !!

[rsb502]

So a tachometer ear, a fuel pressure foot and s**t for brains? Sounds like a truck driver to me!

[doubleclutchinweasel]

So a tachometer ear, a fuel pressure foot and s**t for brains? Sounds like a truck driver to me!

You tell 'em, 'Dog!

[rsb502]

I fit that criteria pretty good actually! Especially the last part.

[Green Dash]

I used to double clutch on every shift when I drove a 300/5 spd. F model because it worked best, hardly ever use the clutch now except for stopping and backing up.

Thats just what i was gonna say! truthfully,i think now i'd be hard pressed to get a clean shift using the clutch!......................................Mark

That's also my experience with older Macks. I used to float the downshift from 5th to 4th but everything else was with the clutch. I've since developed some funky half-clutch thing where I clutch out and float in. Don't ask.

With the Fullers I float except for certain circumstances where double clutching would work best, such as when starting on a hill.

[felicello122]

I always use the clutch, thats why it is there.

[dds92780]

I used to drive my old R with twin stick and the tachometer was broken and the so was the speedo and i drove it forever until i got pulled over by a cop he said i was doing 50 in a 45, asked how fast i was going and i told him based on the engine noise i thought i was doing about 45 to 47 and he coulldn't give me a speeding ticket because when he looked at my speedo it was stuck on 45!!! So he gave me an EQUIPMENT WARNING. Lol, I had all those gears memorized

[other dog]

That's also my experience with older Macks. I used to float the downshift from 5th to 4th but everything else was with the clutch. I've since developed some funky half-clutch thing where I clutch out and float in. Don't ask.

don't have to, I do the same thing!

[Doffer]

I use the clutch always on the mr688s. I love upshifting because i can leave the jake on full and catch the next gear quicker but if I'm driving a freightliner I just float the gears. Only clutch for stopping and reverse

[ognomdrol]

Every truck is different . Some like a clutch and some will float perfectly. Do what the truck says to do .Don't listen to "SuperTrucker" at the truck stop. That is not him parked next to you .