doubleclutchinweasel
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Posts posted by doubleclutchinweasel
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By the way, Gunny, sorry we kind of went off-track there! Didn't mean to hijack your thread! But, it happens sometimes on here! Squirrel!
No offense meant to you either, Joe! I actually enjoy these discussions. Nobody around here (work) who can even join in on these kind of things!
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More info...
It adds the "synchro-mesh" box to the discussion.
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E did have a 1-piece also, I think Brocky. Good catch!
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"Constant Mesh" simply means that all the gears are constantly meshed. The alternative is a transmission in which gears actually slide in and out of mesh while shifting. Those are called "sliding mesh" boxes. Obviously, neither the Mack transmission in question nor the Muncie of which I posted a picture has gears which slide in and out of mesh while shifting. So, both are "constant mesh" gearboxes.
Synchronization is irrelevant in whether or not a transmission has "constant mesh". The car transmission is a "synchronized constant mesh" and the Mack transmission is a "non-synchronized constant mesh". If you want to get super-technical, the "synchronized constant mesh" box can be called a "synchromesh" box, which is basically a contraction.
But, make no mistake, these are ALL "constant mesh", by the very definition of the words. The gears ARE meshed...CONSTANTLY.
If you choose to call it something else, that's fine with me! Hey, it's a free country! Go for it, my brother!
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Interesting observation, FWD!
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Kinda like this...
This example shows the transmission in 1st gear.
Input shaft on left turns counter gear ("cluster gear") on bottom. Cluster gear turns each driven gear on mainshaft. Gears spin free on mainshaft. Inner part of sliding clutches (the "hubs") are splined to mainshaft. When outer part of sliding clutch is moved, it locks into smaller teeth on gear extensions and that gear's rotational speed is transmitted to the mainshaft. The brass "blocking" rings can be seen between the sliding clutch and the gear. The sliding clutch ring, the blocking ring, and the tapered teeth on the gear extension make up a "synchronizer".
Notice that the reverse gear is operated by a separate fork, and is not constant mesh. That's why they could grind when going into reverse.
Incidentally, this one looks to me like a Muncie. And, from the look of the shallow helix angles, I'd say we're looking at an M22 "Rock Crusher". Strong, but kinda noisy! Yeah, I've had a few (dozen) of these apart!
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On 10/13/2023 at 3:32 PM, JoeH said:In a synchronized transmission (not what you have) unused gear sets are not spinning until you try pushing it into a gear. Synchronizers match the gear speeds together for you.
Again, car transmissions ARE constant mesh. All the gears are meshed, and are turning any time the input shaft is turning. They are NOT tied to the output shaft until you engage a sliding clutch (which is splined to the output shaft) with a gear (which is powered). Then you transmit power.
Only primary difference (from a functional standpoint) between a car transmission and a truck transmission is the car transmission uses blocking rings ("synchronizer rings") to match the speed of the gears to the sliding clutch. That's why they start grinding when the blocking rings wear out and no longer have the friction against the cones to synchronize the gear speeds.
Lots of the school buses I drove in my youth had worn out synchronizers in them. There were only a couple of us guys who could drive a non-synchro transmission, so we always got those buses! One of them was our activity bus. So, I got to make lots of trips in that one. None of the coaches or teachers could shift it! Benefit of growing up in Macks, I suppose.
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On 10/13/2023 at 7:19 AM, JoeH said:
this is a Constant Mesh transmission
So are the car and truck transmissions, just for future reference.
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Like Terry said, "685" means ENDT-675 237HP Maxidyne engine.
"S" means "6-wheel" (tandem drive axles).
"X" means "heavy-spec". Translation: "beast".
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The type of clutch you have (Eaton, Mack, etc.) will determine the exact adjustment procedure. Most are fairly simple.
That 5-speed has a HUGE step between gears. Upshifting at 1800 will probably drop down to 1200 or so before it meshes up. Downshifting will be about the opposite...pull down to 1200 and then get up to 1800 before slipping into the next gear. You'll get the hang of it. You'll also get the hang of "floating" the gears (shifting without the clutch). Pretty easy. Just feather the throttle to release the load on the gears, slip it into neutral (no effort required), let off or increase throttle to get the RPM right, and slip it into the next gear (again, no effort on the stick).
And, like everybody said, only depress the clutch fully to apply the clutch brake while sitting still (otherwise, they can be a PITA to get into gear). No need to push it all the way to the floor if using it to shift.
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Yeah, does that say "Hoover" on the nose?
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28 minutes ago, Big R said:Hard to tell from the 2 pictures it’s in but it is a one piece windshield. What years was the a model in production
1950-1953, with a few A20s being done in 1954.
Here is a picture of one of the more well-known examples.
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Could it be an A model?
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2 hours ago, D-Day said:
Hey! I’ve got one of those cards too!
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6 minutes ago, 67RModel said:
The thing about the 12 speeds is they are somewhat scarce and when you do find one they are rather spendy.....at least around here.
I do hear a lot of folks say they really like them. Tends to make them scarce and expensive.
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...bump...
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Or find you another Maxidyne to go with that 6-speed.
I've seen your work, so there isn't much of a limitation on what you can shoe-horn in there! Comes down to cost and availability.
Can't wait to see how it all works out.
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2 minutes ago, 67RModel said:
Just continue with the plan of running an E6-350 and get a duplex or triplex. Plenty of gears and they should bolt together. Don't lug it and you should be fine. For hobby bobtailing or light loads I would think you would not have any problems. I had a B81 that was repowered with a 237 maxidyne and it still had the 18 speed quad box. It was completely fine for just driving around in......
Agree completely. For a hobby truck, any of the Du- Tri- Quadru-plex boxes would be fine, even behind the 350.
But, at the same time, a 5- or 6-speed would probably be fine for a bobtail ride, too. There is still plenty of torque in that 350 to drag it around, even without keeping the RPMs in the sweet spot. Bobtailing my R600 with the 250 Thermodyne and the 15-speed RoadRanger, I usually only used 4th, 6th, 8th, and 10th.
It's be different if you had 80,000# behind it.
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3 minutes ago, 67RModel said:
I thought the all Mack 12 speeds were air shifted for the 10 road gears. The difference being with the compound low could be air shifted with a switch on the dash or a second stick on the floor. Someone else might know better....
From what I have researched in the past few minutes, I think you are 100% right. The difference seems to be in how the deep reduction is operated (air or stick).
I'm just not sure what LTK was wanting to know. Maybe I read too much into his question!
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Maybe you need this...
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So, again...
Are you looking for something with NO air at all? Or were just just wondering about the shift pattern?
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Actually, it looks like it also had an air shift portion on it.
So, are you looking for a 12-speed with ONLY 2 sticks, or a 12-speed that ALSO has 2 sticks? LOL!
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My Mack CF795
in Fire Apparatus
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I was thinking along those lines. Water is supposed to weigh about 8.33 pounds per gallon (at room temperature of 70° F). If you have access to a scale, weigh it empty and full and see what the difference is.
Even allowing for minor differences in the weight of the water (based on actual temperature) and errors in weighing it, it should be pretty easy to tell if it's 500 gallons or 1,000 gallons.