I have a vibration in the drivetrain that is driving me crazy. I can feel a vibration or shake at any speed and it gets worse the faster I go. It feels like it is coming from the back wheels since I feel it more in the gear shifter than in the steering wheel. I can see the bed shaking around at highway speeds.

So far I have done the following:
-Installed new U-joints in the rear drive shaft- No help
-Had drive shaft balanced- No help
-Removed rear tires to have them balanced-No help
-Inserted "Magnum" balancing powder in rear tires- No help
-Installed new rear tires along with "Dyna Beads", did not have tires balanced- No help
-Noticed rear U-joint seemed loose, replaced U-joint- No help

Any suggestions?

 

bent rim ??????????

 

Put it on the rack and run it with a vibe meter at diff locations so you know where to start rather then the whole truck

 

If its a harmonic/fast hum like vibration then it mostly driveline problems. If its more of a shake/wobble then its something bigger that spins slower like your tires or rims. I cant beleive it shakes so bad that you can see the bed move. Thats really bad. Maybe a bent axle?

 

I agree with KATOOM sounds like when I had a bent axle in a old truck.Try jacking up the back end and supporting it on axle stands, put it in gear and watch the wheels from the back. If a axle is bent you will see it.

 

your sig doesen't say if it a quad cab if it is check your carrier being

 

Also remember that if you are seeing the bed move, it is really the cab moving. The bed is hard mounted to the frame, where as the cab is mounted by rubber mounts to help with passenger comfort.

 

Maybe a flat spot on the tire? or a separated internal belt in the tire?....I had a defective tire once but it was replaced at no cost to me.

 

If you notice it alot during a lug or starting out, the rear drive lines may not be aligned. This happened to a buddy of mine. He loosened the carrier and moved it over to the pass side as far as it would go and no more vibration.
It's worth a look.

 

I had a ring gear missing a tooth that gave me very bad vibration that was on Toyota but I too threw a bunch of parts at it to get it right.

 

I was just thinking that maybe your u-joints are out of timing.

 

I agree with Katoom, check to make sure you properly indexed the spline to the universal joint positions after you installed the new joints. What you want is the rear and front yokes in the vertical position. By rear and front, that means the u-joint mounts on the differential, and the yoke that is on the transmission side. Then the center yoke may require pulling the spline apart and moving that yoke (and the entire rear driveline) anywhere from vertical up to seven splines clockwise of the vertical position. Clockwise is as the clock moves, and using the rear differential spline as a reference. So, facing the rear of the truck, first make sure the center yoke aligns with the vertical position of the front (transmission yoke), and then drive it. If the vibration is present, move that center yoke a spline at a time to the right (as you face the rear of the truck), and keep trying until the harmonic vibration disappears.

Since you are going to be next to the rear carrier bearing anyway, check it for looseness or dryness when you have the spline apart. This bearing is usually replaced when the u-joints are replaced, but sometimes it is overlooked. Also, be sure the spline that extends behind the carrier bearing are greased. That should have happened when you pulled the rear shaft to replace the u-joints, but I have seen people replace the u-joints without pulling the spline.

On the 3500 it is also possible to get severe vibration when empty and have it go away when the truck is loaded. If that is the case, insert about 1/8" of spacers between your rear carrier bearing and the frame bracket to lower the shaft angle.

 

Never thought RCW!!!!!!!!!!!!!!