Proper Downshifting Techniques

Discussion in 'Experienced Truckers' Advice' started by FlatBedNewbie, Oct 6, 2022.

  1. FlatBedNewbie

    FlatBedNewbie Bobtail Member

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    Hello, new to the forum and to trucking. I just got my commercial licence (AZ) about a month ago. Got hired the day after my test with a company that does flatbed. I have a few questions.

    We are heavy when fully loaded around 140,000lbs. I have been with a trainer for the past few weeks and he says that I downshift too much. I will anticipate a slowdown or a stop light and will downshift all the way from 18-5 splitting every gear on the way down then to 3 when getting close to where I want to stop, then switch to low or 1 once stopped. I'm using the Jake the whole time and not touching the brakes until I reach the light or wherever I'm stopping.

    He says a transmission is more expensive than brakes and to use my breaks more, not downshift as much and stay in a gear, coast up to the light and then switch to low or 1 when I stop.

    I haven't grinded a gear since I've been in the truck and have been practicing braking and applying throttle with my toe to downshift while braking.

    What is the correct way to downshift when coming to a stop when loaded?

    My second question is going up hills, I try to keep the rpms no lower than 14-1500 until I find a gear that will take me up the hill and then ride it out. Is this correct?

    Third question. The truck they are giving me is a 2013 Kenworth T800, I've been driving a 2019 T880. I tried driving the 2013 and throttle was so touchy I ended up going for a bull ride on my first take off lol. Is this normal for an older truck?
     
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  3. AModelCat

    AModelCat Road Train Member

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    If you're not grinding, you're doing minimal, if any, wear.

    Ever price out brake parts? For just a straight forward shoe and drum replacement you're looking at about $4k in parts to do 8 axles. Add about 8 hours of labour at $200/hour (give or take) to that as well.

    Whatever minimal wear you're putting on the transmission by shifting a few extra times will never exceed the cost of an extra brake job over the lifespan of a truck IMO.
     
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  4. Kshaw0960

    Kshaw0960 Heavy Load Member

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    Going up hills it depends on the engine but I downshift at 1200-1250 rpms. Shifting down at 1400 is just wasteful. If you doenshift at 1500 rpm’s like you mentioned that engine is just screaming. The goal is to downshift just before the engine lugs.

    There really is no need to downshift every gear. Let’s say I’m cruising interstate speeds and see slowed traffic ahead. I will skip every other year. Maybe more than that. (10 speed this doesn’t apply).
     
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  5. SmallPackage

    SmallPackage Road Train Member

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    I’d bet a million bucks that the way you are downshifting to bring that kind of weight to a stop and controlled speed is actually better for the truck, and you’d get twice as many miles out of the brakes and u-joints without hurting a transmission then your trainer would.
     
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  6. AModelCat

    AModelCat Road Train Member

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    You should see some of these guys that come past where I work. 3rd stage jake and then in the last 50 feet before the stop sign they hammer the brakes. Yeah that's got to be so much better for the truck :rolleyes:
     
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  7. SmallPackage

    SmallPackage Road Train Member

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    Old timers would always tell us youngsters that the trans gears were put in there for three reasons.
    1) to smoothly, seamlessly, and effortlessly accelerate.
    2) maintain a cruise speed at desired gear selection.
    3) bring the truck to an easy stop without relying on the brakes.

    drivers rely on their brakes and jakes WAY to much. One day hit the peddle or flip the switch and nothing works. Knowing how to down shift is all you can do.
     
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  8. MartinFromBC

    MartinFromBC Road Train Member

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    You called :)

    There is nothing wrong with downshifting as you slow, its the proper way to do it, but while slowing In a 13 or 18 speed i don't split gears, just drop whole gears.
    I don't think you said what engine you have, sorry tired, been a long day.
    Generally speaking don't downshift at say 1500 rpm, more like 1300 ish, unless it is really steep, and you know that it won't pull the gear you're in, then 1500 rpm is a good idea, because climbing a steep hill you lose speed so fast when out of the power to downshift.
    As long as your not forcing it into gear, or excessively grinding it is all good.
    If someone tells you that they never grind gears, just smile at them and wink, because they are full of BS.
    Don't float gears until you have lots of experience, use the clutch to shift, it avoids shock loading the drivetrain.
    I have a bad habit of 2 foot driving, my left on the brake, and right on the throttle to slow down and downshift. But some people swear its a bad idea, just hard to stop after 35 years, i was taught that from day 1.
    Never rush, never panic, be as gentle as is reasonable, work the motor in the meat of its torque/hp band, and I also don't believe in screaming the motor at high rpm with the jakes on as I descend. I see guys descending at 2000 rpm for the extra hold back, but since I own the trucks I don't do that, 1700 rpm is plenty for me.
    Once you find that gear you can climb or descend those hills at comfortably, stay there, don't be too quick to say upshift just because you can, if you can easily split a gear, and still pull it on the way up by all means do, but sometimes its not worth it, unless near the top. If its a long hard pull, and a warm day, i switch the fan on before reaching the bottom of the hill to just start it cool, but nowadays it seems most trucks don't have a manual fan switch, so don't worry about It, just a 35 year old habit of mine again.
    If you're pulling over to stop immediately after a hard pull, double the idle down time before you shut it off, i try to idle in gently to my destination if possible and just give it a 2 minute idle down.

    Don't pump the brakes either on a long steep downhill. Give it a fairly good brake application lets say 30 seconds, and then let them go if you can for 30 seconds so the air can cool them some...of course that is only if safe to do so.
    Those run away lanes you'll see on ugly hills, never ever let your balls or ego become to big to say that you can somehow save a runaway, and those are only for other drivers...a real man admits when he is in over his head, and will take it before crashing.

    I personally split gears less than some people do when loaded heavy when downshifting, but mostly split the upper gears while accelerating when heavy.
    If you miss a shift, and you will, stay nice and calm, force nothing, and just simply drop an extra gear.
    Nobody gives a #### if you climb a hill 3 mph slower, but they do care when you break things.
    Also don't forget to grease those slacks regularly, and when cold out don't use a thick grease.
    Drive your own drive, don't worry about someone behind you or trying to pass you, be smooth and smart, its their job to safely pass you if they want to, not you get into a rush and screw up.
    Some ####### a week ago was on the radio griping about the speed my rookie I'm training was driving down a hill. Difference is we both know that stretch of Hwy well, he doesn't. It starts off like no big deal, then gets steeper and steeper, then throw in 6 sharp turns with a rock bluff on 1 side, and huge drop off a cliff to your death on the other side, and its narrow, as in 2 trucks going opposite ways just miss each other if they meet.
    I stayed off the radio, and told Melissa to ignore the moron behind us.
    Another driver coming toward us actually thanked us, and told the idiot behind us to shut up, and we likely saved him from crashing his truck if he had gone down there fast.

    Good luck driver, shiny side up...your trainer is a bit of an idiot, but it happens.
     
  9. MartinFromBC

    MartinFromBC Road Train Member

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    Whew, sorry i just realized how long that post is, my bad.
     
  10. RockinChair

    RockinChair Road Train Member

    I was taught to downshift until I found a gear in which I could accelerate, and then maintain a steady speed in that gear with the RPMs above peak torque.

    Yes, those T-800s with the "floating pedal" are way too touchy. I had the same experience with a 2007 model T800.
     
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