Eaton Super 18 & 13

Discussion in 'Trucks [ Eighteen Wheelers ]' started by rrw811, Dec 19, 2011.

  1. Dec 19, 2011 #1
    rrw811

    rrw811 Light Load Member

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    Hi there, I have been doing some research on Eaton Super 18 and 13 speed transmissions, I havnt been able to find out a few things. How long have these trannys been made that feature 2 overdrive gears, being .86 and .74? I always thought that on a standard 18 17th is direct (1:1) .My dad talks about double overdrive trannys from years ago , but the way he makes it sound is that you would have your first overdrive of .74 or so and then one even lower then that, is that correct? I would have to believe that these super 18/13s are really nice at keeping rpm range optimal, any comments from owners of these? Thanks !
     
    rrw811, Dec 19, 2011
    rrw811, Dec 19, 2011
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  3. Dec 19, 2011 #2
    Mr. Haney

    Mr. Haney Road Train Member

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    The first Super 18 was introduced in the later part of 1994 or early 1995

    The Super 13 were introduced later around 1999 or 2000, all the Super 13 speeds were two overdrive gears RTLO18713

    The early 18 speeds could be had in two different final drive ratios. You could order a RTLO18718A or a RTLO18718B. The A Ratio was a 0.85:1 in 18th gear with 17 being a 1:1 ratio. the B ratio was a 0.74:1 in 18th gear and a 0.86:1 ration in 17th gear for a double overdrive. The single overdrive A ratio trannys was discontinued from the RoadRanger line up many years ago

    The double overdrive your Dad is talking about was a hybrid taking a single overdrive transmission and rebuilding with the gears switched around in the case. These couldn't hold up to big horsepower engines too long. The reason is they generated too much heat and would burn up. The double overdrive would be faster than the 0.74:1 ratio of today's trannys this is why they built so much heat.
     
    Mr. Haney, Dec 19, 2011
    Mr. Haney, Dec 19, 2011
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    rrw811, HISPEED428, rollin coal and 1 other person Thank this.
  4. Dec 19, 2011 #3
    KW Parts Guy

    KW Parts Guy Light Load Member

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    KW Parts Guy, Dec 19, 2011
    KW Parts Guy, Dec 19, 2011
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  5. Dec 20, 2011 #4
    Hammer166

    Hammer166 Crusty Information Officer

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    Mr. Haney, I'm guessing you know this, but for these other guys---

    The RTLO Super 13/18s are already "turned round." They have a mechanism in the shift tower that reverses the shift rail motion in the right gate, so that they have a normal shift pattern rather than the "big hole up on the dash" pattern that was once so common (and confused the hell out of newbies!)
     
    Hammer166, Dec 20, 2011
    Hammer166, Dec 20, 2011
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    rollin coal Thanks this.
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