Ok so I got the vacuum disconect system locked now so my front axle is it like a one piece. Is it normal for the front end to vibrate above 55 mph, or is this a U joint? I dont notice any vibration below 55 but at that and above it's steady thing. This jeep is my daily driver and before this I had no 4X4 and no indicator light, now at least I have 4X4 still no light, but this vibration is freaking me out. Thank You all for your help.

Also everything was fine up to 75 mph before I locked the vacuum system

 

prolly just a u-joint. so check the axle and front driveshaft joints. but also check your front pinion bearing by pushing up and/or in out where the driveshaft attaches to your front axle. there should be no up/down or in/out movement. is it leaking by chance?

 

no no leaks, and it only does it when the 2 piece front axle is locked, I'm doing U-joints on thursday so I hope that will fix the problem. I figured I would at least repack the front bearings while I'm there. Any U-Joints you would suggest? I dont really wanna use the auto zone brand, but dont have alot of cash for really good ones.

 

No front bearings to repack, it's a wheel hub assembly. Have you checked the u-joints on the front driveshaft?

 

oh damn see I'm so used to old trucks I didnt even know that. I havent checked the front u joints yet, I just figured I would replace them since I intend to lift it and run bigger tires.