vibration question?? help me!?

[SuperRanger91]

OK when I'm going down the road my truck vibrates a lot and its all in the seat so it must be coming from the rear. I broke my short rear drive shaft and had it professionally rebuilt. Could it be out of balance or would a bad pinion bearing cause it to vibrate also?? And it did vibrate before I broke the shaft so I'm thinking its the bearing. And the vibration gets worse as I speed up so if I'm on the interstate and let it vibrates bad and if I let out of the gas or let it out of gear its even worse so what could it be??

 

[Will]

Is the truck lifted? If you have a simple, single u-joint at each end, the angle of the joints has to be the same. The joints also have to be oriented the same--which the driveshaft shop knows. It seems like the truck has a lift on it, maybe a tall one, and that the rear axle needs shimmed to point it at the transfer case.

Pictures and details would help.

 

[SuperRanger91]

Its stock, its a super cab so it has the two shafts in back and the stock size tires, I had 31s on it for a while and it vibrated less and I haven't crawled under it to see if my rear flange has play in it. Should I start by checking that?

 

[jhammel85]

Might want to try rotating your tires to see if it changes too.

 

[AgPete139]

Manually crawl underneath and shake your driveshaft. It could be the center support / carrier bearing, connecting both halves of the driveshaft. The rubber wears out over time.

I wouldn't blame it on the rear axle pinion bearing just yet. If that goes, then your gears are out of mesh, and you'll definitely hear a grinding humming sound.

And like Will suggested: check your u-joints.

 

[SuperRanger91]

Thanks for all the help and I'll have to get under it soon because I have replaced all the u joints and when I broke my short shaft the shop put in a new carrier bearing so I'll have to check it all over again. Thanks guys and I'll get back with ya soon