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Post by budfan on Apr 23, 2004 14:40:49 GMT -5
Hi, I enoy this site a lot I get a lot of useful information here but I have a questons about down shifting. What are the proper RPM's for each gear in a 10 speed or Super 10? And is it best to Double Clutch or Float the gear ? Hope these questions does sound crazy, but help from folks who have been in Trucking for a while helps. Thanks
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Post by truckertom on Apr 23, 2004 19:46:16 GMT -5
There are three aspects to shifting either up or down: Speed, gear selection and RPM. If you have a truck rolling 35 mph and you select 6th gear in an 8 speed at 1600 RPM, the gear shifter may well fall out of your hand into the gear.
So there is a certain RPM ranger form one gear to the next, if you rev a truck up to 1600 and shift into the next gear, there is going to be about a 400 RPM split between gears. So if the truck remains at the same speed, it should go in at 1200 RPM. The opposite is true of down shifting. Take it out at 1200, rev it up to 1600 and put it in. Double clutching or floating doesn't matter, the RPMs are the same. The only difference is the clutch.
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Post by budfan on Apr 25, 2004 0:18:13 GMT -5
Thanks for your reply Truckertom. I guess the different geared Transmissions, Such as 10 speed, Super 10 and 9 speed with O/D will work in the same RPM range. I've drove a couple of different types a 2000 Freightliner 10 speed, 2001 Volvo 10 speed and (9000 Ford 9 speed with O/D ). The Ford and Freightliner Up shifting and down in those Rpm ranges are smooth. But the Volvo that's another story. I had to get to the 1800 to 2000 rpm because of the the lose of RPM's was fasters even floating the gears. Maybe it is the gearing maybe not. Anyway Thanks Again
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Post by truckertom on Apr 25, 2004 11:19:48 GMT -5
Now, there are differences in engines too! A Detroit will take forever to drop RPMs, a Cat will have a little faster feel to it but a Cummins is FAST! The RPMs rise fast and drop fast. So different engines have a BIG hand in how the same transmission works.
I had a group of students that came out of a truck that had a Detroit in it, and my truck was an Old CFI truck with a nine over and a 400 Big Cam Cummins in it. They hated it! For one full day, they did nothing but scrape gears and cuss my truck.....Day two? I taught them to float it, by day three they started liking my training truck that had the nick name "The Red Headed Throbber". When their instructor returned to work after four days off, they didn't want to go back to his Detroit!
I told them that there was nothing at all wrong with a Detroit, just had a different, slower feel to it. You have to use a Cummins Throttle like you have a rotten egg between your foot and pedal, and you don't want to break it!
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Post by fozzie on Apr 25, 2004 11:37:49 GMT -5
You have to use a Cummins Throttle like you have a rotten egg between your foot and pedal, and you don't want to break it! LOL! That's a great way to describe it, Tom! I'll have to pass that along to my instructor. One of our trucks has a big Cummins with an extremely touchy electronic throttle. Nobody gets behind the wheel of #218 and drives well until they "warm up" a bit... even seasoned drivers. It sure is a kick to drive once you get the feel of it. And talk about power!
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Post by budfan on Apr 25, 2004 23:20:54 GMT -5
Thanks Tom, I did not think about the difference in engines and them having a different RPM range. So the same make of truck such as Freightliner, Volvo, Ford or Mack for example, could have either one of the few engines in them? This is good to know if, I run into a Truck such as the Volvo I'll know why the Rpm fall rate is faster. Then can make the Correction need to get a smoother shift. Again Thanks for the Information
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Post by truckertom on Apr 26, 2004 20:09:53 GMT -5
Oh yeah, you can get any motor you want in them. You can have a row of Freightliners with 3 different engines in them.
But you won't find a Mack engine in a Peterbilt, that would be sacrilige! (I do admit to liking a Mack, drove one for years)
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Post by Pcuthbert on Sept 7, 2004 12:07:34 GMT -5
Some of the difference has to do with the way the throttle controls the engine.
For example, with a Cummins the throttle controls the fuel rate. With a Cat, the throttle controls the RPM.
So with a Cat, you hold the throttle in the same position climbing the hill and the engine controls the fule to do the work. With a Cummins, you control the fuel and need to push the throttle down to keep the power up.
Pat
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Post by truckertom on Mar 4, 2005 10:00:37 GMT -5
I remember the first time I stepped out of a Cummins and into a Cat....it took me a while to figure it out. It was "different". When our students go from a Cat to a Cummins, it takes a little adjustment period.
Some like the Cummins better, some Cat.
I like a Detroit 8V-71.......NOT!
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Post by Rachelle on Mar 25, 2005 1:21:45 GMT -5
But you won't find a Mack engine in a Peterbilt, that would be sacrilige! Hahahaha ;D
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Post by truckertom on Mar 25, 2005 10:33:27 GMT -5
Someone told me the other day that Freightliner has bought Detroit Diesel so you can't buy a International, Pete, KW etc.. with a Detroit in.
Now how dumb can you be? Where is the world headed? Next you will have to buy only Freightliner approved toilet paper from your local dealer.
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Post by Scott on Mar 26, 2005 8:03:20 GMT -5
Just so it's two-ply! But then again if it's Freightshaker paper, it'll probably shake and shimmy right out of your hand if you wipe too fast!!!!!!!!!!!
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Post by truckertom on Mar 27, 2005 18:54:16 GMT -5
As long as there is a moist towelette to finish up the job.....I tell my students there are three things a trucker HAS to have. Pepto.. when it wont stop, Ex-Lax..when it wont start, and preparation H when it all over!
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Post by budfan on Apr 1, 2005 15:18:52 GMT -5
And a Gallon size Gator Aide jug if you are between Rest Areas and running late. That is if you have to Wizz, this is for the Guys. Now for the Girls maybe a funnel and some hose. ;D
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Post by truckertom on Apr 3, 2005 10:48:42 GMT -5
Call me old school but why would you want to carry a collection of pee bottles in your truck with you? And correct me if I am wrong but drivers do go down the road peeing in a bottle, is that not unsafe?
Now I can understand the need for the wizz catch all, but dump it out in a toilet. Don't leave 6 bottles of pee on the parking lot for the truckstop attendant (not the smartest guys in the world but still a human being) to handle.
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