Vibration help needed

[jasonl]

Not sure where to post this*** I have a 96 super cab 4x4 auto. I have a weird vibration and I am not sure what it would be. I will try to describe it. If I am going over 55mph I get this bad vibration that comes and goes. It is like something starts shaking and stops shaking starts stops. About every 3 seconds it vibrates for second smoothes out a bit vibrates smoothes out vibrates like a rotational vibration but it's not always there. I have had a truck with bad slip yoke and it's definately not it. I was thinking maybe the center support bearing on the driveshaft so I tore it all down and found out the part I got was wrong, but I don't think it is causing my problem anyhow. I replaced the u-joints even though they seemed fine. I have never felt a tire do this so I am stumped. Anybody else ever experience this? Thanks.

 

[RangerKid25]

i have a 91 ranger that does the same thing. but i got this truck from my uncle and before he gave it to me he replaced the carrier bearing. but i think i just need to get my drive shaft balanced

 

[rangerchase]

put a jack under the rear axle of the vehicle and put it on jack stands, make sure you have a few inches of ground clearence and run the vehicle in the air.if the vibration is still there, you can try removing one wheel and putting a lug nut on the drum to stop it from falling off, try to narrow down where the vibration may be coming from. also, take a look at both driveshafts while they are spinning and see if there is any deviation. if there is no vibration, try putting the front and the rear on stands and running it in 4x4. take a look at all your tires while spinning, as it may be one or more slipped belts. Does your steering wheel shake back and forth as well? Make sure all of your tires are balanced and your lug nuts are tight.

 

[jasonl]

Yeah that is my next step to put it on jack stands and hopefully see something. I also have a "hop" from the rear that you can actually see the bed hopping when slowing down. I thought it was my brakes/drums and I had a leaking seal so I installed all new brakes and hardware, axle seals and drums and it still does it. This thing would seem like it's something obvious. That's why I was leaning towards the support bearing thinking my driveshaft is bouncing around causing all of this. There is a little play in the rubber mount, but I'm not sure what normal is. I'll definately post if I figure it out.