In the rear?? I take it we would need to replace both sides?

 

Its fixed. Replaced the u joints for the rear driveshaft. No more shudder when starting from a dead stop and no more vibration/ noise when you hit 40-50mph. The u joint going to the diff wasnt too bad but the front one had a bearing cup with all the needles gone. The joint felt good after a physical examination when the driveshaft was on the truck but after I took it off, you could tell the joint was bad.
Pretty easy straight forward job, and only about $25.00 for parts.

 

What are the u joints and how did you determine that what was causing the problem? I drove another 10 miles or so today in cold weather (18 deg) and the humming was louder and higher pitched. I am hearing this noise accelerating over 40 mph, decelerating, and doesn't change in neutral or in 4wd. Thanks for the advice guys!

 

I am in the process of doing up a write up with pics, I will post it when finished.
Basically, my mechanic said it could be the u joints. I said they seem to be good and he said that you cant always tell with the driveshaft installed. It would be better to check with the driveshaft off. I figured that I would change them anyway since they were only $25.00. Once I took the driveshaft off - you could tell that one was bad.
I will get the write up with pics done and post it.
Jim

 

Sorry, I didn't take enough pics on this but you can find u joint changes on you tube which give you the basics. Good to have either an FSM or Haynes Manual as well.


http://www.dakota-durango.com/forum/...90#post2876190

Hope this helps someone.

 

Great thank you, my understanding is that u joint connects the drive shaft to the rear differential?

 

Yes they are

 

Hey all, I added the limited slip additve yesterday and i just changed out the u joints on the rear. Didn't fix the humming noise, but now I have new u joints and enjoyed the project and did some preventative maintaince. I put about 800 miles on my truck over thanksgiving weekend and now the humming starts at about 10 miles an hour and up and only stops when im back to under 10 mph again. I am going have a mechanic check out the hubs tomorrow. Thanks for all the help guys

 

Hey guys, so it turns out my loud humming noise was coming from a bad pinion bearing in the rear diff. Mechanic checked it out and repaired it for about $350, now no humming thankfully.

 

Hey sorry it wasn't your u joints but it is nice to know you don't have to worry about them for a while now - and a good learning experience! did my thread help at all? anything I should change?