Hey all, been working through the 2000 discovery, and have noticed the dreaded vibration from what seems to be the driveline. Notice especially under acceleration, can even feel it a bit through the shift selector, almost like it's shaking everything down there a bit. I'm guessing the most obvious explanation is U joints. Found the parts at the local auto store Precision 344 and the centering ball kit.
Quick question though, I got under the truck and only see 4 Joints...Three in the front shaft, and 1 on the rear just behind the e brake. I was under the impression there were 5 total. Am I just blind?

Any other suggestions on what could cause that vibration....Or you all think I'm headed down the right road?

Also, should the rear be changed as well, or just good practice?

THX for input.

Matt

 

No that is correct, the rear driveshaft uses a flex coupler where it connects to the rear diff.
Make sure that you also replace the centering ball when you replace the 2 u-joints in the double cardon.

 

If the double cardon u-joints have never been replaced, you need to do so. However, it is possible that your immediate vibration is coming from the rotoflex coupler. Look for torn rubber around the bolts. You may need to remove the coupler to see the damage, if any. With high mileage, all items mentioned need replacing. As stated, over and over, the double cardon is a critical replacement (irregardless of if it is the source of your vibration or not).

 

X2 on the rotoflex. If it still vibrates after the u-joints, check the Rotoflex..

 

Replace them both with the shafts from Tom Woods.

 

I was experiencing similar symptoms, and just had a tech friend of mine do the work for me on Sunday - he replaced the 3 U-joints and the centering ball. He told me I caught it just in time as one of the U-joints looked like it had all but failed.

The difference was immediate and significant. It surprised me how much tighter everything felt, and I feel so much more comfortable driving the vehicle knowing that I diffused the ticking time bomb before it went off.

Get it done soon, though. To quote our own Disco Mike (who was gracious enough to take my call and answer some questions), "Stop driving it yesterday."

 

I believe it is a waist of money to replace the rear rotoflex, just plan on changing it out as needed, usually between 80,000 and 100,000 miles.