Rpms causing shifting too early....2012 Cascadia

Discussion in 'Ask An Owner Operator' started by trucky909, Mar 29, 2020.

  1. trucky909

    trucky909 Light Load Member

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    ***This is a manual transmission.....not automatic...***

    I've posted before and can't figure this out. I have a deleted 2012 Cascadia dd15 manual transmission.

    The rpms are telling to shift 10 mph before I have to. Before.....I'm in 7th at 25mph....8th at 35mph and s fourth.

    Now....im in 7th at 15 to 18mph at 1500 rpm.....im in 8th at 25mph at 1500 rpm.

    What's the issue here? I had a new cluth put in 7 months ago, and this issue has been going on for almost a year.

    I had mechanic check and adjust ECM and made adjustments about 2 weeks ago. Still didn't fix issue.....

    What do you think the issue is with this....can it be a transmission issue or something? Was the clutch put in wrong?

    Thanks
     
    Last edited: Mar 29, 2020
  2. Numb

    Numb Crusty Curmudgeon

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    the engine doesn't figure out how you want to shift, you figure out how it needs to be shifted.
     
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  3. trucky909

    trucky909 Light Load Member

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    Give me something better than that. You're basically telling me to adjust to this issue. I can't adjust to my truck being in 8th gear at 20-25mph @1500 rpms.

    I need to know why is it like this now, because it wasn't before.
     
    Last edited: Mar 29, 2020
  4. Snow Hater

    Snow Hater Light Load Member

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    What is telling you to shift? The driving I've done with a 10 speed didn't have any indicator other than the tach and speedometer. The truck was a 2016 Freightliner.

    I just re-read your post and your description looks like you have an auto shifter not a manual. Need a bit more clarification please.
     
    Bean Jr. and okiedokie Thank this.
  5. okiedokie

    okiedokie Road Train Member

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    20-25 mph in 8th doesn't sound right.
     
  6. olddog_newtricks

    olddog_newtricks Medium Load Member

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    Do you have one of those progressive shift programs in your software that needs to be turned off?
     
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  7. mud23609

    mud23609 Medium Load Member

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    That year range of cascadia is known for the clusters going bad. Usually it’s the Speedo that ends up being off but sometimes it’s the tach. Bet your fuel gauge is probably wonky too. That’s usually the first thing that starts failing. The fix is to replace the cluster.
     
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  8. x1Heavy

    x1Heavy Road Train Member

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    Your Engine decides when to shift. A properly matched automatic will know when it's time to shift off the current engine situation.

    There are two RPM numbers to shift at up or down. Thats it. Nothing complicated. Road speed means nothing.

    You are not doing 25 at 8th gear. It wont work. Thus instruments are false. Have a shop look at them closely.
     
  9. AModelCat

    AModelCat Road Train Member

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    So don't move the stick to the next gear until the RPM comes up to where it needs to be.

    What's the issue with that. Your hand moves the gearshift, your feet run the clutch and throttle.
     
    Dave1837 Thanks this.
  10. Ivansoto0123

    Ivansoto0123 Bobtail Member

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    Sep 15, 2016
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    What speed are you doing in 9th and 10th?
     
    Bean Jr. Thanks this.
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