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Thread: Eaton limited slip rear end

  1. #1
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    Default Eaton limited slip rear end

    Eaton offers Detroit Truetrac gear-type limited-slip

    Long the choice of road racers and off roaders, the Truetrac is one of the smartest differentials on the market.
    The ability to lay down matching stripes of rubber on the pavement at will is a mandatory muscle car maneuver, but the means of achieving said trick are somewhat varied.

    Traditionally, the limited-slip differential has used friction, either through a series of clutch plates or cone-type clutches, to send power to both drive wheels while maintaining the ability to accommodate varying drive-wheel speeds. Eaton developed the clutch-type limited-slip commonly referred to as “posi,” thanks to its Chevrolet-given brand name, Positraction, and continues to manufacture a similar unit today, actually named Posi Limited-Slip Differential. But clutch-type limited-slip units have their flaws, including clutch plates that wear over time, the vibration they can cause, and the sometimes unpredictable engagement of both drive wheels in unfavorable conditions.

    As an alternative, Eaton also manufactures the Detroit Truetrac differential, classified as a gear-type limited-slip. The Truetrac uses helical gears to deliver torque to both drive wheels, but only as needed. Under normal conditions, the Truetrac operates as an open differential, but when a difference in wheel torque is encountered, the helical gears begin to engage, delivering more torque to the wheel that is experiencing traction loss.

    There are no wear parts, and the Truetrac uses standard lubricants, so no special friction modifiers are required, as with a traditional clutch-type limited-slip differential. Typical driving characteristics are said to be nearly identical to those of an open differential, with no binding or “pushing” in turns. Installation is also straightforward, requiring nothing beyond typical differential R&R. To learn more about how the Truetrac works, what applications it’s available for, and where it can be purchased, go to www.eatonperformance.com.
    - By Terry McGean
    Jack Carter, Tampa, Fl.
    Silver 97 Mark VIII
    Best time: 13.214

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    I installed one in my '93 when I went with 4.30s.

    Actually my install was more of a desire to upgrade to the True-trac differential rather than increasing the gear ratio.

    For the longest time I could not figure out how it works, despite reading all the literature. However, during the 2007 Hot Rod Power Tour, Eaton had a booth at the venues where I learned the actual workings of the true-trac unit.

    Just incase you didn't know, the True-trac differential does NOT function in reverse. Obviously for some of us, that would never be an issue.
    JP


    Boss 5.3L Modular Mark VIII



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    Quote Originally Posted by driller View Post
    Just incase you didn't know, the True-trac differential does NOT function in reverse. Obviously for some of us, that would never be an issue.
    Is there somebody out there that drag races in reverse?

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    Quote Originally Posted by logres View Post
    Is there somebody out there that drag races in reverse?
    LOL, no - but there are 4WD guys who would be best advised not to use these.
    JP


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    This sounds a lot like a Torsen, which I would like to eventually install in my car when it gets gears. I'm pretty sure I know how those work, but does anyone know how this Eaton compares to them? Either way you're looking at a hefty price tag, but there's also no need to rebuild the thing and it doesn't wear out (like the friction material in Trac-Lok clutches) unless it's abused. Eaton says there's helical gears in this thing and it "drives like an open differential" so that tells me they licensed the Torsen design from the current patent-holder which I believe is JTEKT North America. Ideas?

    -Dom

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    Quote Originally Posted by 97blklsc View Post
    Eaton says there's helical gears in this thing and it "drives like an open differential" so that tells me they licensed the Torsen design from the current patent-holder which I believe is JTEKT North America.
    No, the only simularities are they are both 'gear type' differentials. The Truetrac seems to be a Torsen with missing parts. I'm not sure who came first.
    JP


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    Quote Originally Posted by logres View Post
    Is there somebody out there that drag races in reverse?
    I'm quoting myself because my dad now tells me that back in the day, there were some folks who actually did drag race in reverse. He says the popular thing to do was buy a Ford and put an "Ellis" or something tranny in it, then it could go 70mph in reverse.

    Apparently, the propensity to fly out of control insured that this "motorsport" did not endure for very long.

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    Also Wayne....when you're backing up and turning, your car will tend to back up straight and pull the front wheels instead of turn because the carrier will be in full lock up, and on some of the super strong diff. setups, the cars can't back up and turn as well.
    The infamous "Land Shark"

    Also Owned 97 Tan/Tan LSC
    Quote Originally Posted by driller View Post
    OK, I've been owned. Educate me.
    Quote Originally Posted by DLF View Post
    Was he just on vacation? Doubtful, but I suppose it's possible.

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