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    Guest Message by DevFuse
     

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    Power Divider



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    7 replies to this topic

    #1 OFFLINE   ducky698

    ducky698

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    Posted 19 November 2009 - 09:01 AM

    Hi, how well does the power divider work? read the manual on it, seems quite interesting but how well does it work?

    Grant

    #2 OFFLINE   Rob

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    Posted 19 November 2009 - 09:33 AM

    Hi, how well does the power divider work? read the manual on it, seems quite interesting but how well does it work?

    Grant


    Which power divider? Is it Mack's automatic one, (does not require air), or an air shifter power divided? The Mack automatic power divider works well when in good shape but will only keep about 75-80% of driveline torque and keep the differentials together before breaking over. An air locked power divider does not slip until something breaks but should not be left engaged on a solid surface such as asphalt, or concrete roadways where there would be hardly any tire slippage.

    Rob

    Going through life knowing considerably more about nothing than the next person.

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    #3 OFFLINE   ducky698

    ducky698

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    Posted 19 November 2009 - 06:47 PM

    Which power divider? Is it Mack's automatic one, (does not require air), or an air shifter power divided? The Mack automatic power divider works well when in good shape but will only keep about 75-80% of driveline torque and keep the differentials together before breaking over. An air locked power divider does not slip until something breaks but should not be left engaged on a solid surface such as asphalt, or concrete roadways where there would be hardly any tire slippage.

    Rob


    Hi, its the air operated one. am glad they work well, as this thing may end up thru alot of dirt tracks.

    Grant

    #4 OFFLINE   Packer82935

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    Posted 19 November 2009 - 09:15 PM

    Think of a locking or limited slip diff.
    (or third diff.) between the two diffs.

    Break an axle?
    lock it in and get home!

    Slick roads or poor traction?
    Lock it in!
    You will always have two out of four axles pulling, (not all four).

    Packer
    Keep a clutchin'

    #5 OFFLINE   phantom309

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    Posted 19 November 2009 - 09:41 PM

    I'm sure there's better info out there on the internet but here's the basic idea behind a power divider. The front differential has a set of spider gears directly behind the front yoke. This is what is called the inter axle differential or power divider. What it does is divide up the power to the front and rear axles. If both axles are on flat ground and there's no slippage both axles will get the same amount of power but if one axle is going over a hump or is slipping the inter axle differential will allow the axles to turn at different speeds. This setup allows everything to move smoothly without binding. The only problem is, the inter axle differential always likes to feed power to the axle that's easiest to spin. So if for example you were to put a jack under the rear axle and raise the tires off the ground the inter axle differential would put almost no power to the front axle and the back tires would spin in mid air but the truck wouldn't move. In fact all you really have to do is raise ONE rear tire because there is also a differential that divides the power between the left and right axle.
    The "power divider" or inter axle differential divides the power between the front and rear axle equally but as the example shows when you have one axle with zero traction it will apply zero power to the other axle too.
    When you flip the switch and lock the power divider a gear slides up and locks the driveline up so you send full power to both axles. Now, if you were to jack up the rear axle the front axle would get power and the truck would just drive right off the jack.
    There's really no harm in locking up the power divider at any speed as long as all the wheels are turning the same speed but if you're spinning up an icy hill and either the front or rear axle is spinning faster the gear will grind and damage may result. The best bet in that situation is to let off on the throttle a bit so the wheels aren't spinning while you lock up the power divider.

    Some trucks also have locking differentials that lock the left and right axles together. The same rules apply there except that locked axles will cause more binding when going around corners. This binding on turns will make the truck tend to want to go straight ahead. This can be a problem in icy conditions if for example you are trying to make a tight turn. The truck will start to turn well enough but as the binding increases the steering axle can sometimes break free and start to plow a bit. So you have to be careful and give yourself a little more room.

    Using the regular power divider and most especially the locking axles will always cause a certain amount of binding on anything but straight roads so you try to only use them when necessary.

    Jim

    #6 OFFLINE   RowdyRebel

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    Posted 19 November 2009 - 11:24 PM

    I'm sure there's better info out there on the internet but here's the basic idea behind a power divider. The front differential has a set of spider gears directly behind the front yoke. This is what is called the inter axle differential or power divider. What it does is divide up the power to the front and rear axles. If both axles are on flat ground and there's no slippage both axles will get the same amount of power but if one axle is going over a hump or is slipping the inter axle differential will allow the axles to turn at different speeds. This setup allows everything to move smoothly without binding. The only problem is, the inter axle differential always likes to feed power to the axle that's easiest to spin. So if for example you were to put a jack under the rear axle and raise the tires off the ground the inter axle differential would put almost no power to the front axle and the back tires would spin in mid air but the truck wouldn't move. In fact all you really have to do is raise ONE rear tire because there is also a differential that divides the power between the left and right axle.
    The "power divider" or inter axle differential divides the power between the front and rear axle equally but as the example shows when you have one axle with zero traction it will apply zero power to the other axle too.
    When you flip the switch and lock the power divider a gear slides up and locks the driveline up so you send full power to both axles. Now, if you were to jack up the rear axle the front axle would get power and the truck would just drive right off the jack.
    There's really no harm in locking up the power divider at any speed as long as all the wheels are turning the same speed but if you're spinning up an icy hill and either the front or rear axle is spinning faster the gear will grind and damage may result. The best bet in that situation is to let off on the throttle a bit so the wheels aren't spinning while you lock up the power divider.

    Some trucks also have locking differentials that lock the left and right axles together. The same rules apply there except that locked axles will cause more binding when going around corners. This binding on turns will make the truck tend to want to go straight ahead. This can be a problem in icy conditions if for example you are trying to make a tight turn. The truck will start to turn well enough but as the binding increases the steering axle can sometimes break free and start to plow a bit. So you have to be careful and give yourself a little more room.

    Using the regular power divider and most especially the locking axles will always cause a certain amount of binding on anything but straight roads so you try to only use them when necessary.

    Jim


    Most of the trucks I've driven that have had locking differentials, those diffs were locked with the same switch as the power divider....so you were either ALL locked in, or you were open all of the way around....all or nothing. The last company truck I was in before buying my Mack had the axle differentials on a separate switch from the power divider so that they could be locked in independent of the other. In other words, if I needed extra traction but still wanted to be able to turn, I could flip one switch and lock the power divider leaving the center differentials open to allow easy turns. If I needed forward bite, I could flip both switches and be locked in on both sides of both axles. I never encountered a situation where I'd want the center differentials locked without also engaging the power divider, but I suppose that was an option, too. I'm surprised that having the locks on 2 separate switches isn't more common... :idunno:
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    #7 OFFLINE   HK Trucking

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    Posted 20 November 2009 - 06:19 AM

    I'm sure there's better info out there on the internet but here's the basic idea behind a power divider. The front differential has a set of spider gears directly behind the front yoke. This is what is called the inter axle differential or power divider.


    That is correct on the "generic" rears such as Eaton or Meritor, however the Mack power divider is a cam and wedge type, not spider gears.

    .
    "If You Can't Shift It Smoothly, You Shouldn't Be Driving It"

    #8 OFFLINE   ducky698

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    Posted 26 November 2009 - 05:34 PM

    I'm sure there's better info out there on the internet but here's the basic idea behind a power divider. The front differential has a set of spider gears directly behind the front yoke. This is what is called the inter axle differential or power divider. What it does is divide up the power to the front and rear axles. If both axles are on flat ground and there's no slippage both axles will get the same amount of power but if one axle is going over a hump or is slipping the inter axle differential will allow the axles to turn at different speeds. This setup allows everything to move smoothly without binding. The only problem is, the inter axle differential always likes to feed power to the axle that's easiest to spin. So if for example you were to put a jack under the rear axle and raise the tires off the ground the inter axle differential would put almost no power to the front axle and the back tires would spin in mid air but the truck wouldn't move. In fact all you really have to do is raise ONE rear tire because there is also a differential that divides the power between the left and right axle.
    The "power divider" or inter axle differential divides the power between the front and rear axle equally but as the example shows when you have one axle with zero traction it will apply zero power to the other axle too.
    When you flip the switch and lock the power divider a gear slides up and locks the driveline up so you send full power to both axles. Now, if you were to jack up the rear axle the front axle would get power and the truck would just drive right off the jack.
    There's really no harm in locking up the power divider at any speed as long as all the wheels are turning the same speed but if you're spinning up an icy hill and either the front or rear axle is spinning faster the gear will grind and damage may result. The best bet in that situation is to let off on the throttle a bit so the wheels aren't spinning while you lock up the power divider.

    Some trucks also have locking differentials that lock the left and right axles together. The same rules apply there except that locked axles will cause more binding when going around corners. This binding on turns will make the truck tend to want to go straight ahead. This can be a problem in icy conditions if for example you are trying to make a tight turn. The truck will start to turn well enough but as the binding increases the steering axle can sometimes break free and start to plow a bit. So you have to be careful and give yourself a little more room.

    Using the regular power divider and most especially the locking axles will always cause a certain amount of binding on anything but straight roads so you try to only use them when necessary.

    Jim

    Hi, thankyou for the replies, it seems like an intersting bit of gear. we have a lot of muddy dirt roads here, just dont want to get bogged.

    regards Grant




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