Proably just a coincidence but I changed all my fluids a few weeks back (used Royal Purple thruout. (85-140 rear end)
Did a hard tow to Cal a few weeks back and am now hearing a whine that was not there before. It sounds like it is coming fron the rear end but do not know for sure. when i get off the accelerater the whine stops.
(this is the 03 6 speed)

 

Anyone , can't believe no one has encountered this problem yet ???

 

I had the problem at around 18k but it developed over a period of time. DC put a new ring and pinion in it. Now have 40k and so far so good. I run Redline 75W140 after consulting with the DC tech.

 

I am at 90,000 so no warrenty. Proably can turn up the radio and keep truckin ?

 

I think Bill or Hillary put something in to ruin it.

 

nah, anything they do makes things run smooth

 

If the whine stops when you let off gas pedal it IS the rear end gears howling. Do not let the dealer tell you it is not, and make sure you have a dealer that warranties their labor for 12 month/12,000 miles change it. There are very few people that can set gears correctly, and after a couple hundred miles the howl comes back. I had 4 gear sets installed under warranty and finally went to look at gear pattern before they installed diff cover to okay the last install, it was WAY OFF! So I asked the mechanic to re-shim the pinion to get a better gear pattern, he did and I re-checked it and all is well now. This guy didn't have a clue how to set up a rear end and he was the diesel tech at a BIG dealership.

 

this happened after I changed to Royal Purple and towed a 46 foot gooseneck with horse buggies from Mich to Cal and back.
Coincidence ?? am at 90,000 miles

 

Could the howling be a sign of a bad ujoint? Maybe it was just coincidental that you had changed the fluid.

 

I have never heard a u-joint howl. I have heard them make a "chirpping" sound like a baby bird (I assume because they run dry of grease) before going out - but there is noticable play in joint if there that bad.

 

Joints all feel tight. Talked to a friend yesterday who wrenches for Dodge. He said he would expect it is the pinion gear. (350-400 to replace it). Said should do it as there could be metal shavings in there doing more damage.