i have a 2000 cherokee and it is vibrating at all speeds, and it get very bad on the highway. i took out the front drive shaft and it goes away. before i took it out i noticed that the drive shaft will move from side to side. is it normal or is that bad. its hard to explain so here is a picture if that helps.

 

your drive shaft is bad . Replace it and dont drive without 1. Your fluid will leak out and cause you way more prblems than that.

 

thats a front drive shaft nothing will leek out, but im sorry to
say its bad , get another one at a JY

 

That slip-joint that's out-lined in the picture has a grease fitting on it for a reason. It has gone bad because of no lube in my opinion. You can't lose any fluid because the front shaft doesn't slide into the t-case, but bolts to the yoke. Replace that shaft with the same type.

 

how long has been since you greased it? thats something that usually goes along with regular maintenance like oil changes etc. like was said, if it doesn't get any grease the slip joint will go bad and it's easier to just replace the whole ds as opposed to getting it rebuilt with a new joint.