JohnnyH

I've been running Amsoil 75 110 Severe gear for about 5k now and I've noticed a shudder during acceleration from a stop, and also during turns.

I read on the other forum a thread about people who have had luck using the Mopar friction modifier. I know AAM says it is not required because we dont have clutches, but I figured I'd try it. After adding the 4oz bottle the shudder is completely gone. Smooth acceleration and smooth cornering.

These rear ends must have something that benefits from this additive. It really works.

PS. I knew it wasnt my U joints because they have all been replaced on the rear driveshaft recently.

John

Roperteacher

Yes, John Holmes over at Carsondodge.com was the first Service writer to actually try this as a fix for the shudder issues that were coming into his shop. Of course DC and everyone said it would not work as the AAM axle does not have clutches etc.. Well, he did just as you described and it fixed them all!!!! Still doesn't know WHY it works, but is glad it DOES work!!!

I had been running the 75/110 in my 06 for the last 10,000 miles and had no issues. I just bought a new 07 and installed the PML cover and 110 in the new truck. SO far no issues....

CD in NM

I am running the Amsoil Severe Gear 75W140, have the MagHytec Front and Rear covers which add to the differential capacities, have not needed to add the friction modifier, no shudder. At 19K all is going strong, great rear end.

In a straight line takeoff, the primary drive wheel grabs instantly and the secondary is just slightly behind it in it's gear rotation and torque. In a cornering takeoff, the primary drive wheel also grabs instantly, but the secondary wheel is coming around in an arc, so it's grab would be even more tighter in the beginning of the arc, therefore the shudder would seem even greater from the drivers seat. You would also have some torque displacement from wheel to wheel over the distance of the total differential. All this would be even more magnified starting out with goodly acceleration in your lowest gear. Those with standard transmissions have the ability to start out in 2nd gear which would lessen the torque a bit in either the straight line or the cornering.

CD

TurboTed

I noticed the shudder with my 03 from a stop especially when under load- pulling fifth wheel. My brother had the same problem. We added the modifier and it fixed it. So- I had the rear dif. on my 05 done a few weeks ago. I specifically ask for the modifier, but when I pick up the truck, do you think they put it in? Nooop! "Your 05 has American Gears- no clutches, different than your 03, blah, blah, blah!" After first trip with the trailer, where did i end up today? Buying the modifier for my son's 03 and my 05 of course, because just like my 03- the 05 shudders under load!

CD in NM

It does not hurt anything to add the modifier, in fact it probably would be a good idea to just add it to whatever diff fluid you put in, could benefit over the long run where no one has considered. Clutches or not, friction is friction. It seems like more people with the 3.73 LS rear diff have the shudder issue.

CD

PoorMansCat

Makes me wonder abouut my son's '03 half ton??? Its a 2wd with 3.92 limited slip and a HEMI... Its had an intermittent "noise" when turning. Maybe I'll try some additive and see if it shuts it up.