Downshifting from sixth gear to fifth gear

Discussion in 'Experienced Truckers' Advice' started by expedite_it, Jan 6, 2017.

  1. expedite_it

    expedite_it Road Train Member

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    I drive a Freightliner Cascadia. When my trainer trained me on a Freightliner Cascadia four years ago, my trainer told me that to downshift, I must clutch the transmission out of gear, and then rev the engine up 400 more RPM's than the RPM level was when I clutched the transmission out of gear. Then I must clutch the transmission back into gear to complete the downshift. When I do all downshifts except for 6th gear to 5th gear, I am able to almost always successfully downshift using the method that my trainer taught me. However, when I am attempting to downshift from 6th gear to 5th gear and I rev up the RPM's 400 more RPM's than the level of RPM's when I clutched the transmission out of 6th gear, the transmission grinds when I attempt to clutch the transmission into 5th gear, and the transmission won't go into 5th gear.

    However, when I clutch the transmission out of 6th gear and I rev the RPM's up 500 more RPM's than the level of RPM's when I clutched the transmission out of 6th gear, I almost always successfully downshift from 6th gear to 5th gear.

    Why do I have to rev the RPM's up 500 more than the RPMs when I clutched it out of gear to successfully downshift from 6th to 5th when I only have to rev the RPMs up 400 on any other downshifts?
     
    BUMBACLADWAR Thanks this.
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  3. Dumdriver

    Dumdriver Road Train Member

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    Whoa!!!! Mind blown! Is shifting really that hard? I'm not trying to be a smart arse, I just never realized it was that complicated. I just do it and it happens. I couldn't imagine thinking about it that much. I'd literally melt
     
  4. baha

    baha Road Train Member

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    You are moving the hi range button down to low range before moving gear shifter out of gear, if so the trans has a larger step down to 5th gear you must remember to rev. it up a little extra to make it shift like a pro?
     
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  5. AModelCat

    AModelCat Road Train Member

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    Easy answer is: No 2 trucks are the same. Just because both truck are the same model, doesn't mean they're both spec'd identical. I wouldn't read too much into it.
     
  6. noluck

    noluck Road Train Member

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    It's a larger gear step. Therefore you need to get the rpms up higher to match road speed with engine speed.
     
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  7. Dave_in_AZ

    Dave_in_AZ Road Train Member

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    What all these guys said. And you have a little further distance to travel making that shift, so you need the extra revs so its in the correct range when you get there.
     
    Crusader66 and Lepton1 Thank this.
  8. noluck

    noluck Road Train Member

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    I can't imagine trying to watch the tach to get just the right rpm. I guess maybe I forgot what it was like to be new. Just pull the stick out and give the fuel a little light tap maybe two and it'll slide right in. If you tach a little high you'll catch it on the way back down. As peasy as it is easy.
     
  9. pattyj

    pattyj Road Train Member

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    Just imagine how many trainers make things harder then they have to be for the students.I don't know about you but I got nothing from the ops post.I'm all about basic.
     
  10. expedite_it

    expedite_it Road Train Member

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    Dumdriver, i dont find my question to be that complicated. But i will simplify it for you: for all downshifts other than 6th to 5th, i only have to rev the engine up 400 rpm's. Why do i have to rev the engine up 500 rpm's to downshift from 6th to 5th?
     
    JReding Thanks this.
  11. pattyj

    pattyj Road Train Member

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    Are you driving the same style trk as your trainer had?
     
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