Limited slip differential

[mauricio.sanchez.336717]

I am buying a 1995 DM6 original dump truck .

Did it come with limited slip differential as a standard factory option or was it optional? It has a 7 speed maxi torque.

I really liked the truck but not having some type of traction control makes me think about it since I will be driving it in Florida where it can get sticky pretty fast when it rains.

I appreciate any feedback from experienced Mack owners since I'm new to the truck world and want to make the right decision.

Thank you.

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[gearhead204]

take the truck vin# to a mack dealer and they should be able to tell you how it was specked out.

[chu613]

We're not talking about limited slip dif here and personally i never heard about this in the heavy duty world.

Limited slip dif is a pretty high technology used in the automotive word.

On heavy duty trucks we use axle lock, nown as inter-axle or power divider wich will lock your axles together,and wheel locks or dif locks wich will lock your weels on the same axle together.

If that truck has Mack axles wich I think it does you might have an automatic power divider although I'm not sure.

I now that Mack has a patented automatic power divider now but I'm not sure if they had this in '95.

This will eliminate the switch on the dashboard for the PDL ( power divider lock ) wich means that when one of your weels starts to loose traction the PDL will automatically lock the axles together and you'll have traction on at least one wheel per axle. It can be both wheels on the same side or on a x patern.

I was told by a Mack salesman not to long ago that Mack didn't have wheel locks on their axles until 2-3 years ago wich rock my world to be onest so you might not have that.

Traction control is not something that you'll have on that truck because It goes hand in hand with the ABS wich wasn't standard on trucks until late '90.

[thomastractorsvc]

I thought all Mack axles have a built in automatic (built in) power divider, supposed to put in low gear and feather the brakes to engage it, and the inter axle lock is a option.

[chu613]

Inter-axle or power divider (PDL) are the same thing, it depends how you want to call it.

That's what I said about Mack having the automatic PDL.

What Mack didn't have,was the differential lock or dif. lock wich will lock the wheels on the same axle. At least that's what I was told.

A PDL will lock the first axle with the second wich means that the little shaft between the axles will turn no matter what, giving you traction on at least one wheel on that axle until you do the "magic trick" wich is locking your wheels ( dif lock) and then both wheels on that axle will turn with the same speed.

When you have a PDL the first axle will be bigger on the upper front part of it where the PDL gears are and it will always run 10-15 degrees C hotter due to more gears/ more friction.

A truck with 3 way locks means that it will have a PDL and a dif lock wich is usually on the last axle.

A 4 way lock will have a PDL and dif locks on both axles.

[6368]

I was told by a Mack salesman not to long ago that Mack didn't have wheel locks on their axles until 2-3 years ago

I' am not surprised that a salesman would tell you that but it is not true. Mack axles have been available with an interwheel power divider for a long time. It uses "peanuts" just like the Mack automatic power divider.

[theakerstwo]

Just like 6368 just said.You can look at the axle model # and tell if its got the axle locking.

[theakerstwo]

If the carrier has a 1 at the end of it there will be a diff limit slip in it just like the inter axle limit slip.It will have peanuts and a cam in it.

[j_martell]

I thought all Mack axles have a built in automatic (built in) power divider, supposed to put in low gear and feather the brakes to engage it, and the inter axle lock is a option.

Not all....the 88 RD where i used to work has mack top loaders and a switch on the dash to lock the IAD....but no cross locks, useless in Canada in the winter hauling trash....lol

[theakerstwo]

The power divider that has the air lock will have the automatic lock in it also.

[kt_Engineer]

Mack Axles do have a Inter-Wheel Power Divider (IWPD)/Limited-Slip differential feature as an OPTION. This is unique feature not available on Meritor or Dana axles (though some After-Market solutions are available which if used will void axle warranty). IWPD works very similar to Inter-Axle Power-Divider with peanuts/wedges and CAM mechanism. The Bullgear/final Helical gear drives the cage which when spinning will force the peanuts to move up and down which in turn will spin the outer cam and inner cam. The outercam drives the left side axle shaft and inner cam drives the right side drive shaft. The IWPD will automatically torque differentiate when it senses one of the wheels spinning. The CAM mechanism will allow the non-slipping wheel to slowdown and transmits 3 times the torque to it. IWPD can work at speeds exceeding 25MPH unlike the diff. lock feature (which gets kicked out by VECU above 25MPH due to vehicle safety concerns). IWPD is available on CRD150/151, 125/126, 202/203 (previously was available on CRD95/96 carrier series too but currently is not) whereas Diff. Lock became available only with introduction of CRD150/151 & CRD125/126.

IWPD does NOT have a lock-out feature like the Inter-Power Divider Lock-out (PDLO) optional feature. You can order a truck with PDLO and IWPD or PDLO and Diff. Lock but not both. The standard Mack axle offering does not have a PDLO or a IWPD or Diff. Lock. You will only get Inter-Axle Power-Divider (with out Lock-out) and a standard gear differential between the wheels.

The attachment can help explain IAPD and IWPD in detail.

PowerDivider.pdf