Ok, so I did have a vibration in my truck while driving 40-45 mph and then again and worse at 60-67 mph (did not matter if in gear or in neutral, did not matter if accelerating or decelerating). I got under and checked the rear driveshaft to see if the u-joints were bad and honestly, they were pretty solid, but the shaft had a pretty large dent in it. So i took it off, locked the hubs, and drove off in 4wd to confirm the rear driveshaft was the cause of my vibration. Well the vibration went away! However, there was a new vibration at 30-35 mph, but ONLY when in gear and accelerating/decelerating. The gear choice does not matter. Is this another drive shaft issue?? The front driveshaft appears to be fine (no dents, ujoints are solid), but the vibration is pretty damn violent but the truck is silky smooth before and after. Could this just be because the rear driveshaft is out so that is throwing the whole system out of whack??

 

Sounds like you have the same vibration I do. I have replace my wheel bearings chasing after it. I think I'm going to pull my drive line and send them out to be balanced. Might also replace my motor and trans mounts while I am at it.

 

Things to check:

-Driveshaft balance
-Transmission and transfer case flange nuts
-Differential flange nuts
-Wheel bearings

Good luck, I know it can be annoying tracking something like this down.

 

I had significant vibration due to a defect in a front tire (a "hop"). Replaced under (pro-rated) warranty.

 

Well at least I have a list of items to look at now. I just wish it was obvious like the rear drive shaft that was clearly out of balance due to the dent...

 

 

I'd probably check everything else before jumping to tires. I did the same thing, didn't fix mine. Easy way to flush a paycheck down the commode.

 

If tires are on your radar, first try rotating them. Vibration from front v. back tires is very different. Then, before you replace them, rebalance.