I decided to swap out the u-joints on my 2000 Ex as the first salvo in finding a minor vibration. Removing the 8 flange bolts was no small feat, but they finally gave up and I was able to put the entire drive-shaft on the workbench.

Neither of the u-joints show any play, they don't squeak, and they move freely. But it's apart, there's 100K on the Ex, so I plan to change them anyway.

But what I do find is play in the drive-shaft. There's a slight clunk if I twist the two halves above and below the transition. I can also push/pull the front yoke and get a clunk in the same location.

Is this normal for these drive-shafts? This is my first experience with this type of drive-shaft and this seems awfully strange to me!


Thanks,
~Bass

 

Don't think that's normal Bass, but I can't find anything in the shop manual about acceptable play. I remember paying $560 to rebuild mine last month with a new slip joint though...

 

Rockauto sells remans for about $300. No one did you any favors with a $560 rebuild!

 

They only list front driveshafts for my Excursion, and those are $255 plus shipping. I was charged $425 plus an hour of dealer labor and tax to do mine. All in all it was a bargain for the 7-8 hours they spent trying to track down the problem because they didn't charge me anything for the diagnosis.

 

Why fix the joints if they aren't worn? I would look into that slop more before throwing parts at it too. Those joints could go another 50k miles.

What's a salvo?

 

From Wikipedia:

 

$20 for a couple of u-joints and 2 hours on a Sunday afternoon seemed like a good investment in finding/curing the vibration. One u-joint seems fine, the other doesn't feel right so changing them both is a no-brainer.

However, 2 of the caps just won't come off. Heat and a vice grip don't help. Gonna take the drive shaft to my mechanic friend and let him free the last yoke and check out the play in the slip joint.

 

So it turns out that I'm not crazy. (Well, depending on context....)

I dropped the drive shaft and u-joints off with a friend at the Ford garage this morning. As soon as he saw the u-joint pinned to the yoke but the cap not coming free he commented, "oh. I've seen this before". (These are the factory installed u-joints.) And he believes that the slip-joint play may be enough to cause the vibration.

So he'll press in the new u-joints and service the slip joint. I won't get the parts back until tonight (at the earliest) so it'll be tomorrow or Wednesday before I can whether this helped.

 

-- update --

I got the drive shaft reinstalled last night. No change in the vibration. Going to hook up Ford's "Vibration Analyzer" and see what it says.

Honestly, I never knew that there was such a thing. And it infuriates me. Some while back Ford had my F150 to install a new rear end and diagnose a drive train vibration. They kept the truck for 2 weeks, did nothing more than a visual inspection of the rear end, and claimed that they knew nothing of a vibration issue (despite it being on the work order).

Lubing the slip joint did take the play and noise out of it.

 

You broke the "if it ain't broke don't fix it" rule.

 

Nahh... The vibration was already there, which irritated me into action.

I put up with the vibration in the F150 for 140,000 miles. Not gonna put up with it in the Ex, too.....

 

But didn't you change the good U-joints?

 

I did change them both. The front u-joint seemed fine. There was a tick in the back one that could easily have shown itself as a vibration under load and speed.