My truck has a bad vibration starting @ about 70 and at 75 it will vibrate the rearview off. I changed the U-joints and the carrier bearing seems ok. How do you check the pinion bearing and how do you change the pinion bearing?

 

How bout the front drive line?? Remove it, then go from there. Also could be the tires need rebalanced.

 

Your right it was the fron shaft. Now that I have narrowed it down to the little ball joint in the middle of the double jointed end, How hard is this to repair. I think I need a new yoke because the ball wore threw the race or can I put a new race in there with some new u-joints and call it good.

 

glad you were able to do some good problem solving cause the pinon bering is pressed on the pinon shaft so the entire rear end is pulled apart and most of the time the hardening on the pinon shaft comes off and lets the bering move and shift around so you have to replace the ring and pinon too
just so you knoe in the future

 

That's the Cardian Joint....I think you can get a rebuild kit from Rock Auto for it.

 

I havent found one for it yet so I am just driving it like it is for now. How hard is it to change the pinion seal on the front dif.

 

Not very hard. Easiest to use a slide hammer to pull the seal, then use a big socket to install the new one.