I have a 03 Quad, 4x4, Auto, that I pull my 12K lb 5er with..... Truck has been problem free for the 70K miles I have owned it. It has 109K miles on it. Earlier this year, I noticed that when I am towing my camper and travel down the interstate for a while (5O + miles) then exit off for gas or to change roads, I get a really bad "shuddering vibration" in low speed turing or pulling back out after a stop. It really feels like a limited slip differential that is not "slipping". I have had the cover off my diff a couple of times and the pattern looks good as does the fluid with no metal chunks. I have used synthetic oil and even some Mopar additive the second time and it is still there.

Not very noticable if not towing and only does it after driving for a while.

Anyone have this problem or an idea on how to correct. Could it be u-joints or transfer case? Really feels like the rear though.....

Thanks,

 

its amazing how many do the same thing I have 2 trucks that do the very exact same thing. I am also on here to find out why. Im glad I have a little support now.

 

May not be your problem, but front axle u-joints at low speed turns can cause a pulsing vibration if going bad.

 

If it is only while turning I'd also suspect front axle U joint.

A bad drive shaft U joint can also make a bad vibration that is most notable at very low speed and more pronounced when pulling.

You may see a bit of rusty looking stuff around the cap's seal, but you may need to turn the steering to lock and jack up a wheel and spin it by hand to feel it, or unbolt the drive shaft yoke so you can flex the U joint by hand.

If you do take one apart, be sure to match mark things so they get reassembled the same.

 

i replaced mine but it was more of a noise, not so much a vibration. definatly something to check.

 

I don't know if mine is the same problem but towing my 5er at low speeds (like parking lot speed) and turning out of a sharp turn gets me a small wheel shimmy but on the highway she is fine. Doesn't do it all the time. I am not woried as I am about to do track bar/solid bushings on suspension pivot arms. Figure it's too much mushy stuff all getting together and forming a conspiracy on me. Good suspension but too many soft pivots.

 

Front U joint fixed my problems.
I wonder if the no slip additive is causing any issues? I don't think the 03's require it, I have never used it in my changes. Perhaps someone more knowlegeable on that aspect can comment.

 

The 03 manual indicates the additive is used for the Trac-Lok limited slip,

FRONT AXLE
* C205F - Mopart Gear Lubricant 75W-90
* 9 1/4 AA - Mopart Synthetic Gear Lubricant 75W-90

REAR AXLE
* 9 1/4 - Mopart Synthetic Gear Lubricant 75W-140
* 10 1/2 AA - Mopart Synthetic Gear Lubricant 75W-90
* 11 1/2 AA - Mopart Synthetic Gear Lubricant 75W-90

NOTE:
Trac-LokT differentials require Limited Slip Additive in the lubricant. (9 1/4)

Trac-Rite™ differentials DO NOT require Limited Slip Additive. (10 1/2 & 11 1/2)

 

Yeah, ours does not require additive.

I asked Redline about that, whether I should use the regular 75W90 that contains additive, or the other no-additive stuff.

An engineer answered, that the system in the 11.5 AAM does not require additive, but it won't cause any harm either, and the additive actually makes things more slippery and might reduce temp where the gears mesh.

Anyway, I've used the regular stuff (with additive) with no problems all in this truck and the last one.

There were a couple of threads a while back about people using gear oil with no additive and having some grabbing issues with the rear end that went away with additive, though.