The vibration shows up at the speeds of 55-70, only when there is some load on the driveline. If I am driving at a constant speed, no vib. If I lightly accelerate, without loading the engine, there's not much evidence of the vib., but if I push the pedal a little more and load the engine, without downshifting I get the vib. Also vibration when I let off the pedal. This is only noticeable at the speeds of 55-70.
This leads me to believe a u-joint prob, but I cant find any loose, or worn u-joints. There is a little play in the drive shafts at the transfercase, but not anymore than any other 4x4 I've ever owned. I am wondering if the front or rear gearsets are the culprit. Or maybe the transfercase has bearings starting to wear or some other problem.
![Think :-k](./images/smilies/eusa_think.gif)
Any input or ideas will help.
Thanks