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Please Explain Freedom Drive?

Discussion in 'Compacts: Renegade, Patriot, Compass, Caliber' started by Rick Anderson, Jan 13, 2017.

  1. Rick Anderson

    Rick Anderson Well-Known Member

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    But, nothing states the ECC unlocks, even partially to allow slippage for turning on high traction surfaces. It would have to though, so we all assume it does.

    Maybe a Wrangler Owner could confirm this, I would think the Wrangler O.M. would warn about engaging 4X4 on high traction surfaces and trying to turn. The Compass O.M. has no such warnings for engaging 4WD Lock, which I suspect the reason why is because the system recognizes the vehicle is turning and unlocks the ECC, at least enough to allow slippage for the turning.
     
  2. GLHS60

    GLHS60 Well-Known Member

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    The Magna article stated that lock maintains a 50/50 split front/rear.

    ""the system has a manual-select position for a 50-50 torque split.""


    It doesn't say if the lock can be over ridden but it probably can.

    First, the CAN bus (Controller Area Network) monitors signals, principally throttle position, steering angle, vehicle speed, and road texture (an algorithm that includes wheel speed sensor signals). The signals go to the AWD computer, which calculates the ideal front-rear torque split that it anticipates.

    It sounds like a pretty ingenious system for all weather driving.

    I get where you're coming from as to the lack of factory description.

    The full time, part time AWD terms continue to confuse many folks.

    My brother in law still can't understand his older Grand Cherokee 242.

    He thinks part time is for the highway and full time is for off road !!

    He's even older than me and works on his own vehicles, so its not like he's new to vehicles.

    Thanks
    Randy
     
  3. Rick Anderson

    Rick Anderson Well-Known Member

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    Its just occurred to me, the PTU can't have a differential, cause if there was a differential between the front and rear axles and if the ECC unlocks and separates the rear axle from the driveshaft, then the center differential would direct all power to free spinning driveshaft, the front axle would have no power at all, the vehicle wouldn't move at all.

    Yea sure, perhaps the differential is limited slip or locking, but the thing doesn't look big enough for the simplest deferential, let alone a more complicated one. And if it did have an enhanced differential, they would have written it up and bragged about it in the literature of the system.

    The only way I can imagine a clutch pack could modulate torque, i.e. something other than a 50/50 split of torque, is if the clutch pack didn't fully engage and allow some slip. I don't know if that's true, it just makes sense to me. Everything I've read on the ECC's and said it does modulate/adjust the amount of pressure on the clutch pack according to conditions.

    And clearly the system can tell if the vehicle is turning, but does it unlock the rear for every turn or does it reduce pressure in the ECC keep power going to the rear but allow enough slip. I think that would give much better performance to maintain 4WD through turns then to simple switch to FWD only every time you turn.

    Yea, I never liked the terms Part and Full Time 4WD, although its better than we get today in descriptions of the system. I prefer open/limited slip/locked/no differential. I just remember Full Time 4WD means you can use it all the time in all conditions, Part Time 4WD means you can only use it some of the time in some conditions. But, I know where your brother is coming from, Full sounds more capable than Part Time, when its actually part time that is more capable (but only off-road). I once tried to give someone a simplified description of some of the Jeep 4WD drive systems, and said the Wrangler's NP231 had a locked differential, Bob Sheaves jumped all over me cause a NP231 doesn't have a differential. But Bob saw my point, I might have just confused the guy, its just simpler to say its differential is locked.
     

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