I had a pretty bad vibration at 70mph that only got worse the faster I went. Never could go above 80 as the shake was pretty bad. Figured it was the tires, I had two come apart within a month or so of each other and got some new shoes. Still had the vibration, figured it was maybe a bent rim (Noticed one was very slightly bent when balancing the tires). Finally, I had enough and took it to a buddy of mine that happens to be a mechanic for an excavation company. Wheel bearings... Good. Driveshaft tight, no excessive play.... One piece driveshaft so no carrier bearing to worry about. We jacked it up, and put it in gear with the wheels up, and low and behold, the driveshaft was bent. So, got the driveshaft re-tubed and balanced, replaced both u-joints since I was there, and "de-clunked" the slip-yoke. Much better but I still have a vibration at 70, not nearly as bad until I hit 80mph. Now I am sorta confused.

One thing I noticed was the original driveshaft had a large metal ring sorta thing that was toward the back part of the driveshaft... What in the world was it? The driveline shop didnt put it back on (if that was even possible) and have no idea if it was there to cut down on some vibration. Should it be there? I wish i would have taken a pic or two, but I forgot. I didnt notice any play in the rear pinion but I will be honest, I didnt check the transfer case.

Any ideas???

Thanks
Jim

 

Do you know if they ballanced the driveshaft after the repair? Just guessing.

 

I'm not 100% sure but I think that is a harmonic balancer. it keeps it balanced at different speeds. Someone can confirm or let me know how much I don't know .LOL A Curtis

 

It was balanced from the repair. I too thought harmonic balancer, but was wondering why it wasnt put back on... I hope that isnt what the problem is. I am sure he has recycled the steel by now....

 

If you had that steel balancer on there before, and had the vibration, and you still got the vibration with it off, I dout thats the problem. Maybe a bent axle, speaking of the possible bent rim, was the truck hit or did you hit anything, very large pothole, curb, ect???

 

I know the driveshaft was bent. When it was jacked up you could see the the driveshaft was nowhere near straight. I had a friend follow me and he could not see anything out of the ordinary with the wheel in question. I do know the truck was involved in an accident prior to my owning it. The vibration is not nearly as bad now. In fact, coming to work this AM, it seemed like it was the worst when I was maintaining speed on level ground or slight grades. If I get on it climbing a hill, the vibration clears a little, when I let off, its horrible until the speed gets to about 75-80... I may have to pull the axles next week to check those....

Thanks guys