"Cé hé sin" (michael-m-mouse)
10/27/2014 at 16:16 • Filed to: None
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"Cé hé sin" (michael-m-mouse)
10/27/2014 at 16:16 • Filed to: None | 3
| 6 |
Not a great picture, but the shift pattern is:
1...... 2
........3
Having whetted our appetites with a manual nine speeder we continue to what used to be the mainstay of heavy trucks in Europe, the manual 12 speed.
To get here we have one gear lever, two switches and three boxes, none of which has more than three speeds.
In practice you skip several of the lower gears because at low road speeds you don't need such closely spaced ratios, but just for the sake of completeness you could proceed like this:
Lever in 1, range change switch in low, splitter switch in low. We're now in 1L.
We move off and preselect high on our splitter. Nothing happens until we press the clutch whereupon we find ourselves in 1H.
Once we're done with this we preselect the splitter again, press the clutch (yes, you use the clutch – this is a synchro box) and engage second. We're now in 2L.
We continue in the same vein to 3H.
From here we have more work to do. We preselect low split and high range using the two switches and engage what used to be first gear but has now become (because high range) fourth. Now we have, to the accompaniment of hisses and clonks from underfoot because three gearboxes are changing, 4L.
From here on it's a straightforward matter to reach 6H.
RazoE
> Cé hé sin
10/27/2014 at 16:32 |
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Sweet! Going to do a 'Merrican 18 speed next? How my dad drives these, I have no idea.
Drakkon- Most Glorious and Upright Person of Genius
> Cé hé sin
10/27/2014 at 16:54 |
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We have a Ford F800 with a 5 speed box and a two speed axle. Not the transmission, the axle. Did you hear me? Good, let's move on.
Shifter in low. Red button down. Let clutch out, we're moving. You're in 1-Lo
Now, keep the throttle buried, pull the red button,let off the gas and voila la! You're in 1-Hi.
Now, Push in the clutch, shift into second, leave the clutch in, push the red button down, let the clutch out. Congrats, you're in 2-Lo.
Here is the hard part. My employees fuck it up every time. The 2-speed the axle. It only sees torque. It has no idea if you are using a clutch or not. They push the fucking clutch every time. grind-grrrrr-grind-grrrrr lose speed, have to down shift...
It's not as hard as it sounds, but they are all experts and I'm a drooling idiot. Except I drive it smooth and they grind it smooth. BWAH! I'm going crazy!
Don't even get me started on downshifting using the axle.
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Cé hé sin
> RazoE
10/27/2014 at 16:55 |
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Later. I'm only up to 12. Same basic idea though with one change as compared to European (and most of the world's) trucks.
Hammerdown
> RazoE
10/27/2014 at 17:00 |
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If you look at the pattern its not really that difficult to figure out. It's a 9 speed with a split. Going up through the gears is like doing a 4 speed twice. In normal conditions you'll use it like a 16 speed (low gear is almost never used) The ones I've been around you generally don't split the bottom, so it's 1-2-3-4 pre-select high range, shift back to 1 (now 5 because of high range) then split every gear. So wind it up in 5th, pre select 5H (with a different toggle on the shifter) and as soon as you lift it will change gear. Pre-select low on the splitter again, shift to 6, repeat all the way to road gear. A 13 speed is the same way is the same except without the split on the bottom (1-2-3-4). So most of the guys I've seen treat a 13 and 18 speed the same unless they're pulling something really heavy or in a congested area.
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Cé hé sin
> Drakkon- Most Glorious and Upright Person of Genius
10/27/2014 at 17:01 |
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Two speed axles are long gone on this side of the pond. Here's a forum thread by some old guys with memories.
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Drakkon- Most Glorious and Upright Person of Genius
> Cé hé sin
10/27/2014 at 19:35 |
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Well in case you ever need to know, 4-hi is higher than 5-lo so there is no need to use both. Just go from 4-hi to 5-hi.
When it's time for downshifting, it's a lot like double-clutching. As your revs fall too low, you click the button to the down position, just as you hear the axle rattle for the first time, you stab the gas. As that increase in torque hits the gears, it snaps right into place. Again, no clutch. Don't touch it. Then doing whatever revving to the engine is not making it back to the axle.
So, if you ever come to America and the last truck out of town before the apocalypse is a 1989 Ford F800, you can save humanity.