I have noticed a vibration for about 4 months now,It only really happens at about 50 to 60 MPH. I have slowly been eliminating causes. I have put new tires, had them center balanced, Allignment, had the rear end checked and fluid changed.( everything checked out good) just yesterday I noticed when I was heading to San Diego from Arizona, I was heading up the grade, I was doing around 55 took the Overdrive OFF and Vbration got worse ????????? Now this seems a lil weird to me, I havnt changed carrier bearing or U - Joints on rear shaft yet, but this leads me to believe that it is not my Rear drive shaft. Anyone have any opinions ??? By the way I just had a SunCoast TQ Cnvrtr installed about 2 mnths ago. Could there be something wrong with the T.C ?
Please let me here what you think..

Thanks in advance.

 

It could a lot of things , but start with the simple 1st , lose TQ bolts , cracked flex plate .

 

but wouldnt it vibrate all the time? the vibration only happens when iam at 50 to 60. kinda like its a rear u - joint

 

The idea is look at the possibilities , not find a reason to not look at a possibilities .

 

I had a vibration at certain speeds. Turned out the u-joints were going out. Thought is was all kinds of things since they weren't loose or squeaking yet. They were tight enough you couldn't move them by hand once I got the drive shaft off. If you do it yourself, it is an inexpensive repair compared to what other things might cost.

 

I agree , took the truck for a drive with a buddy, once the vibration kicked in we kicked the truck into neutral and the vibration was still there. So Iam gonna lean twords the rear u joints next. Thanks for the help...

 

Have the same issue with my 04. Found the harmonic balancer on the driveshaft was broken off the rubber mount. The local driveline shop replaced the yoke and they said the balancer on the yoke is no longer availabe and replaced it with a standard yoke. 3 months later I have the same problem. This annoying vibration in the driveline at 70-80 mph. I can feel it it the transfer case but no one can figure out what the problem is. My truck is passing 150K with no other issues until now.