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So after getting the truck a tune-up and safety check, I took it down to our local State Beach parking lot (now that all the thousands of tourists are gone) to get a little practice with shifting, and after 3 practice runs, gave it a try on the road.

There's a bit of grinding, but mostly because there's no tach, and I have to force myself to pretend it's loaded, and shift at a much lower speed that I really need/want to....

But on the whole, I thought this wasn't too bad for my fourth try of shifting through a few splits.....

The file was too big to post here, so here's the YouTube link:

I have the recommended shifting pattern for a B61 from a manual, but it's for a triplex. Does anyone have an actual manual page that shows the recommended shifting pattern/order for a quadruplex for both upshifting and down shifting? I know that for the triplex, they point out which shifts can be skipped, because the ratios are so close, and I'd like to know which ones those are....

Mike

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https://www.bigmacktrucks.com/topic/42678-quadruplex-shifting-practice-in-b42/
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Mike

Do are doing better. If you are going to use the clutch, DOUBLE CLUTCH on every shift of either transmission!! When shifting both you actually have to triple clutch.. Watch your left foot in your video.. When you shift without remembering to double clutch is when you are getting the grinds.. If you have any other vehicles with a manual tranny always consuisly double clutch them also so that your left foot/leg just learns do it automatically.. There is basically no difference between the Tri and Quads as you do not use lo-lo for other than off road.

  • Like 2

Brocky

looks like you need to get the basic theory of driving a truck transmission down first. Don't worry about a tach, shifting at the lower rpm is making it a little more difficult also in my opinion.You're better off using no clutch than trying to shift it like a car,will not last long like that.

Thanks for the advice! You're correct to notice my hybrid clutching methods. Some of that is conscious as I'm experimenting with what works best for this truck. I drove a fire truck for years with a 5X2, and I could shift up or down with our without clutching with no problem, so I'm not exactly a stranger to the theory. But I know that every truck is a bit different, and I'm still trying to find what this truck's "g-spot" is for shifting. (I also think that gas vs. diesel makes a big difference) So I've been experimenting with no-clutch/single-clutch/double-clutch, and the double shift, as it's been pointed out, is still my biggest weakness. I think that I will, in fact, stick with a triple-clutching technique for that for now. And I tried the through the wheel method on the double shift, and it'll be a while before I try that again, lol!!

I've discovered that I can shift pretty easily from lo to hi in the aux with no clutch if I remember to not push until the rpms drop (and I'm not using lo-lo at all), and I can downshift the aux with no clutch as well, but the rest will definitely require some more practice, probably more with the clutch than without!

But it's been fun to learn.

In the video, my purpose was specifically to experiment with split shifting. As bigdogtrucker suggests, I normally drive it essentially like a 5-speed, although there are some hills around here where my 150hp 401 doesn't cut it, and the poor thing can't get out of its own way, often requiring splitting at least one or two gears as I have to either split the upshift to keep moving, or split as I downshift while my speed drops going up a hill.

I've read a lot of complaints that people make about the 401 being underpowered for road driving, and I'd have to second that. I'm not sure what the rears are geared at, but top speed downhill is about 47, and I know that it was a city truck, so speed was never an issue, but it's just sad to start out at the bottom of a grade at 45 and a quarter mile later be down to about 20 in 3rd lo!!

dont have much choise alotta times but to shift them both at once,,,otherwise you lose everything,,,looks like you figured that out lol..thier pretty much a pain in the ass,and why they dont use them now.bob

  • Like 1

if he has a 401 gas job he has a TrQ770 quad and the main is toward the driver and auxillary is toward the pass side. splittin can be done with the clutch but shifting the main in the smaller gas job flatheads usually requires the clutch. totally different operating RpM also. gotta really rev a gas job up to shift it around 3000rpm

  • Like 2

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Maddog is correct, my main is on the driver's side, and the aux is on the passenger side. I've been wondering about that. Was that only done on gas? Or just the 401? Or single axle vs. dual? Anyone know what the logic was on that?

And it certainly seems that the aux is a dream to shift compared with the main... It's a lot less picky, and there's a bit more bumping and grinding with the main.

I was also wondering if the main was designed to shift at a higher rpm so that during a double-shift, where the main goes first, you shift at a higher rpm, then by the time you hit the clutch again, get the aux out of gear, clutch again, and move the aux to lo, it's already expected to be at a lower rpm, and designed to work that way.....

That's why I wish I had a tach. I think in the Spring I'll get a cheap digital one and stick it on the dash to try to see what the difference might be between the two and what the sweet spot is for each transmission.

I watched "Twin Stick Pappy" on YouTube about 20 times and got the idea of how to do it. I've only driven around the lot which with 7.49's allows me to use a lot of gears. I've found no clutch to be easier in my limited experience. As you have noted, his sticks are opposite yours but same idea.

Have a blast.

  • Like 1

the bigger boxes, the auxillary on the triplex and quad was closer to the driver. sometimes called the ''hot stick'' cause most of the time it gets used more...... all the smaller TRD77 and TRQ77 series trans used with the flathead gassers had the main closer to the driver. no clue why. the gassers run in the 3000rpm range. they are all tempermental and everyone is different. they aren't as forgiving as a diesel if you change the rear end gears to higher ones to get more speed. sometimes it screws up the smoothness of the shift.

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No worse them my first summer in my truck. You will find that you have to rev it up high enough to make the splits. If not, the gearset slows down too much to match it. With a gasser you have more rpm range then a diesel so it has to be more forgiving. A slower, more methodical shift rate will make it smoother. If you try to SPEED through them you'll just grind things up.

Good job so far.

  • Like 1

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Larry

1959 B61 Liv'n Large......................

Charter member of the "MACK PACK"

 

One of the first trucks I drove was like a 1968 DM. I was told it was a chrysler v8 gasoline engine with a 5+4. In the beginning I would shift all 20 gears even when empty just because I was an 18 year old gear head. I remember the transmission as very smooth and easy to shift. Once I learned it well you could jump around in it pretty good depending on your load and how steep of a hill you were climbing. Slow down and double clutch.

Thanks for all your feedback!

I've been driving it a bit the last couple weekends, and am definitely getting a much better feel for what gear and/or what split I need to be in for various situations. As I'm worrying a little less about that, I'm finding that the shifts are getting a bit smoother as well, and I'm getting a better feel for where the main and the aux each drop in best - and it is definitely different between the two. Since I don't (and can't per law with antique plates) drive loaded, I'm now more interested in shifting it right for my driving conditions, which means driving it like a 7 speed (splitting 2nd on the start) with the occasional split for hill climbing.

But I will still experiment with shifting/splitting through all the gears, just because it's fun to be able do it! ;-)

gmerrill - like you, when I bought the truck, while I was waiting to get it towed home, I watched the Pappy video a couple dozen times so I'd have a good mental picture of what to do. I think it was a huge help and made the learning curve a lot less steep when I went out to do my shifting experiments. I'd recommend that to anyone who's just starting off with a triplex or quadruplex....

Glad you are having fun and be careful. I would always double clutch up to 5th on the main and then double clutch from say LO to HI on the auxiliary as one shift. Then double clutch from 5th to 1st as a second shift. That is simple and works.

Another helpful hint to anyone wanting to learn to double clutch. Anything you drive that has a standard will shit just fine with a double clutch. A standard car or pickup truck can give a guy good practice in a smaller easier to handle package. I drove truck so much that it is just a habit to double clutch.

  • 2 years later...

I know this thread has been up for a while but I just picked up a quadruplex truck and bring it back to life.  I reading everything I can find I found two shift tags and the items posted in this thread.  One of which notes: “Do not use split with main transmission in 5th speed”.  Can someone please explain if this 18 or 20 speed transmission and why this information conflicts with the shift order pictured in Phildirt’s post from November 15th, 2015.  Thanks!

14 minutes ago, Rev.NitroNick said:

I know this thread has been up for a while but I just picked up a quadruplex truck and bring it back to life.  I reading everything I can find I found two shift tags and the items posted in this thread.  One of which notes: “Do not use split with main transmission in 5th speed”.  Can someone please explain if this 18 or 20 speed transmission and why this information conflicts with the shift order pictured in Phildirt’s post from November 15th, 2015.  Thanks!

There were two versions of the quad box, a 722 and a 7220, the 722 is a direct in 5th gear which you can split, the 7220 is a overdrive in 5th gear which you do not split, you go from 4th high to 5th high gear.   hope that helps!!    terry:MackLogo:

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