While towing my boat on vacation I started to notice a slight vibration when towing while turning, only from a dead stop , like at a traffic light. No vibration while going straight forward from a dead stop. I unhooked the boat and tried to duplicate it and could not. It would only do it under a load. I did a rear fluid change around 15K ago and went with a higher capacity cover and using Amsoil. So, I took it to a shop in FL and explained all to the mechanics there. Consensus points to the rear end and they added the additional fluid modifier, even though other tech bulletins report that it is not necessary. Well, I couldn't feel the problem after that, but I didn't want to try too terribly hard as I was far from home. My biggest concern now is am I still looking at repairs shortly down the road or is the magic snake oil the answer? Also, is there an after market diff that's an improvement over the stocker? Sorry this is so lengthy. Thanks.

 

What does your 03 have for a rear differential? Does you manual state that you should add the friction modifier when servicing? I know the AAM in the 2004 and newer do not need the fluid modifier as there are not clutches in the AAM's. 2004 was the 1st Dodge I have owned and am not familiar with the earlier years.

 

sounds like it was lack of the additive since it will show up more when towing . believe your truck will be fine

 

Mine is the AAM Tracrite, or so the tech said when he looked it up

 

I did not need to add any in my 03 but i have the AAM rear end.After I changed it I made a longe trip of 6.788 miles out west and had some hard pulls.Every went very good on the trip and is still good. My totle weight was 22.900+ lb. Good luck

 

Well today I got the boat cleaned up and went to pulling the monkey snot out of every corner I could to see if I could get it to vibrate. Evidently the magic snake oil worked; hopefully it will last. Guess I'll do another diff change soon and add the voo doo to the mix and hope it lasts a good while; thanks for the input guys; this place is always my first tech lookup

 

Mine does the same and has for 75k miles. The friction modifier does help even though its not listed as required. The last change I forgot to pick it up and went without for a few days and it showed right away. A bit irritating but I'm not worried about it. I think its just the conical rollers not rolling smoothly when loaded.

 

I was having the same probs.
It started whn I did my first fluid change and went to Amsoil. The dealer added the Chrysler additive and it stopped for a short while.
When it started again, I then switched to RP and it quited down some.
My front diff seal started to seep after Amsoil.

SO, I dumped the Amsoil from the front, drained the rear RP and put it in the front, and went to Valvoline Dino gear oil (90-140wt) along with a tube of the Transgo Possi lube and have never had another problem and the rear works just fine. Still have the LS!

 

I wouldn't worry about that vibration or chatter. Mine started doing it at about 100,000 miles and I went to 140 weight oil to fix it. Now at 172,000 and all is well.

These are excellent diffs and you should have no failures with it.

The friction modifier or the heavy oil might make it slightly less agressive as far as limited slip is concerned. When starting out from a stop with the front wheels turned the diff is trying to lockup so it chatters a bit. Not an indicator that it's about to fail.

 

I switched mine to 75-140 Royal Purple when it started doing that and haven't had a problem for nearly 75,000 miles.

 

My diff took a dump at 130k. Started howling about 40mph and getting a harmonic at 25mph. Removed the rear diff cover and noticed lots of flake on magnet and in fluid. Wonderful tracrite gears were coming apart and tore up the drive side of ring gear. New carrier, ring and pinion, and bearings were needed. Unfortunately had to go with stock carrier again and not too many choices for quality gear sets. Just something to look for when you pull the cover.

 

Up until recently (2004? 2005?), the standard LSD used clutches; just like Ford and Chevy. In any LSD that has clutch plates, you must use the additive, or you get chatter, poor performance, and early wear.

In recent years, dodge went to an LSD like the Torsion II and the Detroit TruTrak; all gears, not clutch pack. This design should last longer in heavy duty applications. It can be trickier to set up properly. And there's some performance advantages. But, there is no need for additive in the gear only diffs.

 

I think we all get that it is not a factory recommendation. But some develop chattering as described above and the fix is additive or heavier weight oil. It's something that some of us have tried with success.

 

My sons (my old truck) 96 does the same thing all the time. Like at a drive thru going real slow around the circle it chatters really bad. We know that is a pinion bearing. Its been getting worst over the last couple years and is more apparent going to the left.

I have another friend with a 2001 dodge 3/4 ton 3:55's, high mileage with the same thing and it also was a pinion bearing and slop in the gear box.

Next time your under the truck crab the pinion end of the shaft and give it a shake left and right and up and down.

Dave

 

WOW I might have gotten the shaft form dodge. Paid for the LSD option and looks like like basic spider gears. Same on my buddies 04. I went to the dealer and they said all in the computer and the ABS using the breaks and no clutch pack. They said the AAM system spider gears are supposed to be tighter than other spider type gears and when the breaks are applied it will send power to the wheel with traction. Guess that was all non sense. It has never worked or at least like the Dana 80 in 99. My 03 is helpless unless in 4x4.