Hey guys I got a 94 zj I bought recently it's lifted on 31's, I kinda don't drive it as much because of the mpg but everytime I go on the freeway right before I hit 60 mph and over, I get this weird intermittent vibration, and it's only when I'm on the gas if I let off, the vibration goes away, which tells me it couldn't be a wheel hub or alignment since the steering wheel don't shake either; right when I got it I replaced the t-case output seal and the one that goes on the rear pinion 'cause those were leaking, and lately (I've been using it more often) I've noticed the one seal on the t-case is leaking a little again, so my question is , could this be a transmission issue or t-case or maybe my drive shaft is causing it, tranny mount? It once did it pretty strongly when I hit the overdrive button to get a little more power going up a hill
Any help would be appreciated, thanks

 

got the u joints changed on the rear drive shaft the vibration is still there, has anyone ever dealt with this problem? could it be the slip yoke wearing out?

 

Grab the front drive shaft and see if there's any play in the u joints or flange. There should be no play in the front shaft.

 

I would look at the u joints and drive line angles.