2006 5.7 Hemi Mega Cab 4x4 Shudders on acceleration. Really noticeable When pulling my boat. Lifted the truck on a rack, thinking there must be a U-joint ready to let loose, but found nothing. The center carrier does not look bad, but I can push the shaft up and down a good half inch. Maybe more. The mechanic I am working with is a trusted guy. I would like any input from the forum, however, to be more informed when I meet with him again on Tuesday. The truck shakes on acceleration, especially when pulling a load. Trans shifts fine, truck has 170,000 miles on the clock. We are leaving for Vacation and are taking the boat. I would like to have anyones input on what this could be, so I can be more educated when I meet with the mechanic on Tuesday.

 

It definitely sounds like a u-joint or your carrier bearing is going bad even though I know you said you checked those. Don't know what else it could be, good luck and let us know when you find the problem.

 

It was the rear U-joint. Cap was cracked and needle bearings were gone. I can't believe I looked at it time and again and missed it!!! Having all three replaced as they are original and I have 180,000 miles on the clock. So glad it wasn't the trans, as we are leaving on vacation saturday and pulling a boat 700 miles!!

 

That's great news, glad you found an easy fix, have a good vacation.