Hi there everyone. I have a new ram 3500 cummings dually with the limited slip axel option. In checking this axel to be sure it works I jacked up the truck an with trans in neutral I turned one of the rear wheel sets. Without limited slip I always notice that the other wheel opposite of the one you are turning will spin backwards. With the axel on my truck the wheel set oppisite of the one I am turning does nothing at all. It was my guess that with the locking system that wheel set should start to turn in the same direction with the set I am turning after I have turned the wheel a certain ammount. I turned the wheel at least five revolutions with the same result. My next test was to take the truck sideways on a decent hill and slowly turn the steering full lock in the uphill direction. By doing so I made the uphill rear wheel into the less traction wheel and assumed as it started spinning the downhill wheel would start spinning as well but it did not.
Perhaps someone else has tried to figure out the limited slip axel and can explain its advantages since so far it seems to be no different than a standard axel. Dan

 

So far with my experience, they do not work that well. It will make the loaded tire spin a little, but not enough under extreme situations. I have had luck aiding the limited slip with a little brake modulation to keep all wheels spinning.

 

I think the new AAM axles use a Torsen style differential – like a Hummer. Torsens use no clutches or friction devices and don’t perform in the same manner as an old-school limited slip.

http://auto.howstuffworks.com/differential10.htm

 

Found this on another Diesel site, and thought it would be of interest to all 3rd Gen Owners with LSD's




The following is a S.T.A.R. Center Case Report:
Report created Jan 6 2004
Updated Jan 13 2004

Customer says his trac-rite rear diff is not working?
GCK1: 01/06/2004
Recommendation/Solution
Review AAM Trac-rite diff characteristics. Rear diff is working or truck wouldn't move. It will overrun like standard diff if operating on extreme differernces in surfaces. (Ice under one rear tire with other tire on dry pavement.) No further action.
:GCKI:01/06/2004
The 2003 heavey-duty Ram uses and American Axle helical differential or Trac-Rite. The Trac_Rite differential is different then Trac-Lok in that it uses helical gears (Trac-Lok uses clutches) to transfer power to the opposite wheel when slippage occurs. The transfer of power from wheel to wheel is torque sensitive and must have both wheels spinning (not stationary) to function. It is possible for the Trac-Rite differential to not send power to a wheel if is not spinning. Example: Accelerating from as stop and one wheel is on ice and the other on dry pavement. If accelerating to fast, the wheel on the ice may spin and never send power to the whell on the pavement side. A slower start may be necessary to start the vehicles momentum.
A written test procedure for Trac-Rite is not listed in the repair manual and the following points should be noted:
Testing the Trac-Rite differential while the vehicle is lifted and turning one wheel by hand, the opposite wheel will turn in the opposite direction. This is normal.
If the Trac-Rite assembly has and internal failure it will lock axles 100% side to side.
To test the Trac-Rite process, raise vehicle on appropriate lift, place into gear and accelerate quickly (hard launch). A second technician will witness both wheels turning at the same speed at the start of the acceleration.
Another test for Trac-Rite is to slowly drive vehicle in an open area and completely turn wheels to one direction and accelerate hard.. The vehicle will experience tire hop or shudder. This is normal. Trac-Rite differentials do not require friction modifier and should be used only with SAE75W-90 GL-5 synthetic fluid PN 05102232AA.
The Trac-Rite differential found in the American Axles may look like the helical gears have ground away the case. Six small half circles are noticable on the side of the differential opposite of the ring gear. These openings are desinged for oil flow and are not the result of the helical gears grinding through the differential. Please do not replace the differential case or any other part of the axle due to these openings.
Note: All American Axles require Mopar lube part# 05102232AA synthetic and does not use a friction modifier.
RAB40: 01/13/2004






Looks like both rear wheels must be rotating for it to operate properly , so not much help starting out on a slippery surface in 2WD.

Nothing like the old positraction with clutches the way I read it.


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I have the limited slip on mine and I think this limited slip is much stronger than my previous GMC. When take off on a turn on pavement or on dirt I can tell the both wheels are pulling hard by the marks in the dirt and the sound of the wheels on the pavement. I'm not sure what's different in the designs but I'm much happier with the way the dodge performs. I think it gives me real 2 wheel drive in the rear. Just my observation.

 

That will explain ...If I am rolling, it seems to engage fine. If I am stopped, I have to use a little brake modulation then it works fine...now we all know!

 

Thanks, that answers all of my question. I could not figure out why I could break the rear end loose and get it sideways in the rain but then get stuck in the ice and have only 1 wheel spinning.