power divider question

[mackniac]

When I bought my truck the guy said that there was the power divider on the diffs,and the air switch was in the dash,

yeah right the switch was there but no line going anywhere , now I wonder if the diffs. are realy instaled with the power divider, is there an easy way to find-out a diff. with powerdivider vs without .

here are mine :

[MACKTRUCKS4]

Yes there is a power divider there. It does not have air controls on that one, your truck was probable built with an air shifted divider but the rear was changed at one time and the unit they put in has a standard power divider. The way they work is if you have a tire spinning, spike the brakes while it is slipping and it should through the power to a different wheel. An air shifted one you would just flip the switch to lock the divider in. Never seen a rear without a power divider.

[mackniac]

Ah so they all have a power divider but some have an air actuated lock and some don't , am I understanding properly ?

so according to what you wrote they are not the original diff then ?

If i spike the brake will this not stop all 4 wheels ?

thank you for the help .

[MACKTRUCKS4]

They all have power dividers. The front rear was probable changed, not sure about the back one. You only spike the brakes for a second, just enough time to transfer power to a wheel that has more traction.

[mackniac]

I'll try that brake spike and try to find-out if the diff have been changed .

[Challenger]

You can always call or stop by a dealer and have them look up your rears. Just ask them if it has an air lock powerdivider on the front rear.

Front rears always have a powerdivider. Rear rears never have a powerdivider. Mack rears

Look at the pinion housing on both rears, notice the front rear housing is larger, thats because the cams and wedges/peanuts for the powerdivider. Powerdividers with air lockout have a cylinder haning off of the side.

You have a powerdivider, it just doesnt have air lockout.

[Lmackattack]

Looks like you have the mack automatic power divider. It locks in when wheel slip is detected. You won't know most times when it is engaged. It's nice because most of the time it locks in before you know you need it. The manual "air switch" power divider you had to lock it in before you went off road and remember to unlock it before you ran down the road and burned it up..both have their good and bad points...

[Jeremy_Brault]

as i have been told the air lockers still have the peanuts and are still automatic just that you can lock it in before you get slippage. that way you know it is locked up and cant let it go. maybe im wrong correct me if i am but my old mack mechanic told me that.

[Vladislav]

You guys told most wrong.

Power divider doesn't lock itself totally but distributes torque between axles by a special way.

Common diff has distribution 50/50. It means when you ride both wheels (semi shafts) have a half of the torque provided to an axle.

When one of wheels starts to spinn the torque on a spinning wheel limits its traction on slide surface i.e. too small.

Diff distributes the same amount of torque to another wheel. It's small also and isn't enough to move vehicle.

That's why we are getting stuck.

Diff of the kind with peanuts (Mack patented) distributes power in relation up to 1/3 so if one wheel spinning another one get 3 times more torque then a spinning one.

It's 3 times more but usually still not enough.

Then you applying brakes.

Brake torque increases torque on a spinning wheel although another one get it 3 times more. That is what you feel as "enough".

It's all described very good on here in the Wiki support forum.

Just look: http://www.bigmacktrucks.com/index.php?/topic/21251-mack-power-divider-info/

Another way is a diff with lock (air lock or correctly say "air activated lock")

It works like any other diff lock i.e. just put both shafts together as a solid one.

This way you must use a vehicle like a one without ANY diff.

No distribution of power so all 100% of torque can go to any of two wheels (axles if it is interaxle diff).

Just don't forget that a torque stressed one shaft can also be 100% instead of only 50 when you drive unlocked.

[mackniac]

thank you all ofr the info .