Acceleration Vibration

[Big8inchlift]

Anybody out there have any clues as to why I would be getting a wicked vibration out of my 92 when I accelerate? I just bought it and it has a Rancho lift, looks like about a 3" or 3.5" and 33's on it. Everybody I ask says to check the tires and wheels, but i don't think thats it. It's weird, i get a bad vibration when i give it gas, but as soon as i let off, it's smooth sailing, so i know thats not it because they would vibrate due to speed no matter if i am accelerating or not.

 

[BroncoJoe19]

Anybody out there have any clues as to why I would be getting a wicked vibration out of my 92 when I accelerate? I just bought it and it has a Rancho lift, looks like about a 3" or 3.5" and 33's on it. Everybody I ask says to check the tires and wheels, but i don't think thats it. It's weird, i get a bad vibration when i give it gas, but as soon as i let off, it's smooth sailing, so i know thats not it because they would vibrate due to speed no matter if i am accelerating or not.

You're right... it is NOT your tires.

My guess would be that it is a bad universal joint.

You could TRY to shake your drive shaft at the joint, but unless it is extreemly bad, you won't be able to perceive any play in it.

 

[Broncobill78]

Sounds to me like a driveshaft issue. While it might be a bad U-joint I'd suspect a bent/dinged (keep in mind that a rock-ding can & will throw the shaft out of balance. Look for any dents anywhere along the shaft) shaft, out-of-balance condition or most likely a bad slip-yoke. You can inspect it visually to see if it's thrown a balance weight. If the slip-yoke has any lateral play in it then it's toast, packing it with grease *might* diminish the problem slighty but it'll be a temporary & incomplete fix but enuf to help you confirm the problem. Try this, put the truck into 4WD (I assume you have auto hubs so you'll want in to already BE in 4WD before you move on to the next steps. If it has manual hubs the the order of operations can be changed) and then remove the rear driveshaft so you can tool around in front-wheel drive. If the vibration goes away then you pretty much have your answer. If it doesn't go away then you're back to looking at the wheel balance or possibly an out-of-round tire. A 3" lift isn't nearly enuf to skew the driveline angles to the point of vibration. Does your driveshaft have a double cardan joint (AKA Constant Volocity joint, it's the one with *two* U-joints) at the transfer case or does it have a ******. Now maybe it's something exotic like a f*cked up pinion yoke but at that's really more like seeing hoofprints and looking for Zebras instead of horses. Pull the rear shaft, drive it around on just the front axle and see how it rides.

 

[Big8inchlift]

Awesome information. I'll try both of those!!! Big thanks for the quick intel!!!

 

[BroncoJoe19]

Awesome information. I'll try both of those!!! Big thanks for the quick intel!!!

Ofcourse BroncoBill's post's are pretty darn complete, so the one thing that I would add ot it, is if you pull your drive shaft, you can pull the caps off of the one Ujoint that you will unbolt to get it out. IF you can see ANY grooves at all in the shiny part under the cap, it should be replaced.

Have fun driving around in front wheel drive /emoticons/[email protected] 2x" width="20" height="20" />

 

[eddie bauer]

I have the same issue in my 91, I replaced the u-joints, rebuilt the double cardan unit, new wheelbearings, balanced the tires, and changed the pivot and radius arm bushings. Balancing the tires helped ALOT! It needed all the other stuff anyways. It only does it at about 50ish or so under power, it dosen't do it all the time so I figured the vibration was just something I had to live with. I will try and remove my rear driveshaft even though it looks clean, no dings and see if it makes a differnce thanx for the advice.

 

[Rednek]

if it were your tires then it would get worse as you get faster. so it is not the tires. even though it is good to keep a frequent check on them. maybee your driveshaft is messed up. look into a new driveshaft. as we all know drive shafts go bad in lifted trucks faster then non lifted.

Rednek