13 vs 18 speed.

Discussion in 'Trucks [ Eighteen Wheelers ]' started by belltransit, May 3, 2011.

  1. dieselpowerrules

    dieselpowerrules Light Load Member

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    Feb 24, 2011
    Wisconsin
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    Hey now, I resent that, lol. I have only been driving for four years, and I've had the same truck and have never torn anything up, but I know what you guys mean when you mention people taking off in way too high of a gear. There was this one guy at the company I used to work for who would take off loaded to 100,000lbs on an upgrade in the high side of a ten speed! He dropped the rear ends out of a couple of different trucks and couldn't figure out why. :biggrin_25526:
     
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  3. freedhardwoods

    freedhardwoods Light Load Member

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    Feb 4, 2011
    SW IN
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    I drive a 13 speed with 3.55 gears and rarely split any of the gears until I hit 13th. I start 80,000 pounds on flat, solid ground in 2nd without touching the throttle until I'm moving.

    A good driver can make a bad setup work. A bad driver will tear up all kinds of things.

    The epidemic of bad drivers we have these days is why so many companies are going to automatics. They don't tear them up as fast as a manual.
     
  4. freightlinerman

    freightlinerman Road Train Member

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    What's the final over drive on a 13 speed with a double over drive? I never understood what people meant, they said the over drive was normally opposite on the shifter.
     
  5. lostNfound

    lostNfound Road Train Member

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    Home of the Stampede
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    The top two ratios are 0.86 & 0.73.
     
  6. SL3406

    SL3406 Medium Load Member

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    Jan 10, 2011
    Oklahoma
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    I think they were talking about the older double over RTOO 13 and overdrive RTO 15 speeds. The top gear position was against the dash.
     
  7. melpromud

    melpromud Medium Load Member

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    Jan 29, 2010
    camden ny
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    The top gear in a 13 or 18 is .73 over just like a 9 or10 speed. The double over is 12 or 17th at .86 over where one gear down in a 9 speed or 10 speed is 1 to 1. I think what people ment about over drive being opposite of normal is that years ago you last two gears were backwards. High gear was actually forward up agains the dash. Thats not the case anymore. Direct drive and over drive transmissions have the exact same shift patterns. With todays trannys the 13 and 18 are the only double overdrives but high gear isn't any higher than a 9 or 10 speed. The second OD is between 1 to 1 and high gear. 12th in a 13 and 17th in the 18.
     
  8. Rock hauler

    Rock hauler Light Load Member

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    Deridder La.
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    The RTOO 13 was .62 overdrive the RTLO is .73
     
  9. terrylamar

    terrylamar Road Train Member

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    Oct 8, 2006
    Austin, TX
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    I have an Eaton Fuller RTOC-16909A transmission converted to a 13 speed. I, also, have upgraded my ECM with a Bully Dog, increasing the torque to over 1800.

    This is a former lease truck which I bought. I have been having transmissions problems since I first leased it, hard shifting primarily. The clutch needs replacing now.

    I was thinking about buying an 18 speed and installing it. From what I am reading on here, that may be overkill. Would I be better off just rebuilding the trasmission I have now along with a new clutch.

    I have been worried about the torque being too high for my transmission.
     
  10. lostNfound

    lostNfound Road Train Member

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    That transmission is factory rated for 1650 lb-ft torque.
     
  11. Les2

    Les2 Road Train Member

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    kicked back in my lazyboy...
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    Unless you are going to go with a 2000 ft lb torque trans don't bother to upgrade.

    I just bought a Lipe 1 clutch that is rated for 2400 ft lbs for less than a eaton spicer.
     
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