Baffled by Vibration/Shutter
 

O.K. first off I've read every thread and post on this issue and my symptoms don't match. I have developed a viration/shutter over the last week that seemed to come on instantly. I just noticed it one day when taking off and it occurs between 20 and 35 mph. And it's worse under light throttle. The more I put my right foot in it the less I feel it. It doesn't happen when slowing down or coasting in neutral. I can also feel it a little when accelerating at cruising speeds 60-65 and I can hear what seems to be a whistling sound breifly (a second or two, then goes away) from what I thought was my rear sliding window, but it's not. I assume its coming from under the truck. I've read all the posts on u-joints and driveline angles but alot of those only noticed it when slowing down or accelerating hard or pulling. Mine seems to be less noticeable when accelerating hard. Any guess before I start blowing a bunch of money chasing this?

Sounds like a u-joint to me...

Did you get under there and check them all?

If not, start there.

Visual inspection looks good. No grease splattered on anything, no dents in driveshaft. Everything looks normal. I should also note that if I roll the window down I can sometimes (50% of the time) hear what sounds like a clicking sound coming from under the drivers door. Doesn't do it so much now as I have turned the Smarty way down. Used to daily drive it on 5-Moderate TM.

what about popping, cracking noises when you hit bumps? how about when shifting from drive to reverse? does it clunk?

I think any kind of shudder on take off, or while driving usually comes back to ujoints (I could be wrong). as far as inspecting them, dont just look at them, grab the drive line and twist, see if the ujoints look loose, mine were so bad (I have one that still needs to get replaced but thats another story) that I could push it with my finger and it would move.

so I would say really look at those ujoints first.

No odd sounds when shifting from drive to reverse. I will say the low pitched whistle/screech sound is getting louder when at cruising speeds.

This sounds like what my Ujoint next to the tranny did when it went out. Mine looked fine on the outside, but I always just take out the 4 bolts on the diff and slide the shaft out. couldn't swivel the output at all with the shaft out. Not hard and real easy to check ujoints up close that way. Not sure if you have a carrier on the shaft how hard it is to remove that way.

I'll find out. Got 3 Precision greaseable u-joints going in tomorrow if I get time. Hope it fixes the prob.