Vibration under hard throttle........ (sagging springs)

[craigmpak]

1043221

Hey I'm new to this board so I just want to say HI!!! Seems like a cool place to hang out..........



In any case, I have a question. When accelerating hard with my 6 cyl 92 YJ 5spd, I get a funny vibration coming from under me. Seems like it's the rear but I could be wrong. What can I look for to correct this problem? It's smooth as silk if I drive normally.



Also, my front end sags a bit (close to the bump stops on the axle), am I better off getting a leaf added or do I just get longer shackles? What would you guys do?







Craig[addsig]

 

[MudderChuck]

1043226

Vibration under acceleration usually indicates a bad U-joint on the drive shaft. Can also be a worn rear bushing in the tranfer case (usually throws a bit of oil also). Springs that sag are prone to break. My advice is to have them re-arched, tempered and hammered or replace. If you have them re-arched gaining an extra inch or so of lift is no problem. But it´s helpfull to have a pattern or a good spring, so the metal worker has an idea of how much arch to put in the sring pack.[addsig]

 

[CTJeeper]

1045281

From the sound of it, it seems like you have axle-wrap, which occurs because of weak rear spring. I have the same problem on my '91 I6 YJ, but i have a 4" SkyJacker lift on its way so hopefully that will remedy the problem. [addsig]