Originally Posted by papaduck

I'm not saying that it is not a u-joint, but check the harmonic balancer on the front of the crank shaft. It is supposed to be checked every 30k miles. Check for the rubber splitting and separating and make sure the 2 marks are opposite each other and aligned on the inner and outer steel parts.

Originally Posted by BLACKBEAR

They have a fluid one that is a lot better than the one on there. I have seen a lot of good reports on them,

Originally Posted by smartin1

Just went through this also. But I had 150k miles. Replaced the 3 u joints on the front shaft, still had the vibration. Had done the ball joints and wheel joints last year. Then replaced the 3 rear u joints. The center u joint was rusted and nearly froze up. But the real issue was the carrier bearing. It was nearly frozen up. It can not be lubricated. While the rear drive shaft is out, you must replace the carrier bearing. Its essential. But don't pay $200 for the dealer bearing. NAPA has it and I found the part # on this forum. Its NAPA bearing HB88508 and I paid $67.49 for it. NAPA counter said they couldn't get the carrier bearing. Give them the part # and they'll have it. So now I have all 6 drive shaft bearings with grease fittings and a new carrier bearing. Should be good for 100k-150k miles hopefully. If you lose a new u joint prematurely, its because of bad install or a cheap bearing. Pay up for good u joints, and use a bearing press or vice. The vibration was making me crazy till I got it solved. Good luck.