I was chasing a vibration coming from under the drivers floorboard, concentrated on the tunnel where my gas foot sits... I held my hand in various places on the floor to pinpoint the strongest area of vibration.
Since I had my driveshafts sand blasted before I rebuilt them including the cardan joint and u-joints. (I combined a 1998 and 1999 Cherokee so I had no reference points marked on this driveshaft). Since I could feel the vibration concentrated near my right foot, the first thing I tried was flipping the front driveshaft 90 degrees. Still had the vibration. Then I took the front driveshaft off and vibration went away.
I checked the u-joints and cardan joint. Everything seemed ok.
I installed the driveshaft and pulled the front tire off so I could have a better look at the fit to the front pinion. Low and behold I see a gap between the straps and the u-joints. Tomorrow I will remove the straps and try the other ones I have.
I suspect the straps I have on the front may be off the back driveshaft of my donor Cherokee.
We'll see.
Just posting this in case others ever run into this same issue.
Mike

 

Good to know.

 

i had the same problem on mine. mine had play in the slip part of the drive shaft. grab it at the slip joint and try to wiggle. If it moves there that's you problem. I got a good used one on ebay for about $60.

 

Thanks... My original driveshaft had that issue at the slip joint. I have the one in off my Donor Cherokee now. Must have got the rear straps mixed up with front. They are indeed different, now need to take it for a drive after I finish my lift install today.
Thanks
Mike