So a week ago my Ex started growling and howling and shaking like I was on a bucking bronco! Of course we were scheduled to go out of town for the weekend. A 700 mile round trip.

I pulled the truck into the garage, jacked up the rear and checked U joints and the drive shaft. All seemed normal. I go to pull it out and hear a huge clank. I have the wife jump in and I watch the drive shaft as she puts it in gear. Drive shaft and pinon twist a good bit before the wheels move... I put it back up and put a pry bar in the space on the rear u joint and have her twist the wheels. Wheels move and pinion stays still.

So we cancel the trip and i pull the rear end, disassemble, clean, swap bearings and reassemble. I found that the oil is burnt and all the bearings are shot. You could see the wear in the races. With 245k on the Ex it was due for some love.

As my wife and I are putting the drive shaft in, she pulls on the ratchet and it goes into the u joint hub and the shaft slides over about an 1/8 inch. It didn't do that when I tested the u joints out.

So out comes the drive shaft all the way and off to the work bench. I replaced the u-joints 60k or so ago. Greased every oil change.

Three of the four caps had plenty of grease and the needles looked awesome! The fourth cap had no needles and a huge pile of powdered metal and no grease.

When I pulled the slip yoke on the front, I found that two of the splines in the slip yoke are missing! You can see where they fractured, split and are gone. The rest of the splines in the yoke are intact and look fine.

The splines on the stub end have no wear. The blue coating is in tact and had plenty of grease. I greased them when I did the last batch of u-joints.

I am hoping that maybe what I found and experienced will help someone else out.

We got the Ex buttoned up tonight and put 45 miles on it around town. No leaks, drips, errors or noises! The Ex is very quiet now. Hopefully I get through the winter before I have to do the front axle.

 

I'm presently in the middle of completely re doing both drive shafts. After towing a cargo aboard a full vehicle trailer I developed a harmonic vibration, and all my U joints were spitting grease. Since the front 4wd shaft was avail from Ford as a plug-n-play unit, I went that route for the front, not so for the rear. I brought the rear to an old timer driveshaft man a couple weeks ago. Was supposed to be simple, just replace the U joints, and both halves of the slip yoke if needed. The U joints were no problem, I asked him to put the best Spicer ones in, when he ordered the OE style slip yoke male and female halves, he was unhappy with the tolerances once inserted into each other. I had the original large spline and generously spaced apart. He suggested going to the newer style slip yoke, siting tighter tolerances, and a stronger connection due to the tighter splines. I think my mileage is around 225,000, from looking at my original U joints he said they were original. I'm curious as to the longevity I'll get out of my new rear drive shaft. What grease-able brand U joints did you use, and what did you replace them with this second time around? Maybe I was simply lucky to have my originals last that long.

 

60k ago, i put in NAPA brand u-joints. Which are usually reboxed spicers or dana parts.

This time O'rielly brand from China. I needed the truck back up and running. Plus $17 verses $45 from NAPA.....Plus NAPA was closed Christmas Eve..

I am going to go out on a limb and say that towing and running a tune might put a bit more strain on things in the drive line area.

 

BTW I was told not to use the HD u-joints. Reason being is the metal is more brittle supposedly...

 

I'm definitely keeping an eye on mine now, since I'll know the usage and maint history of things going forward.

 

I was in a rush last year to replace a destroyed universal joint and used a NAPA heavy duty ujoint.

I replaced it again a year later with a SPICER. One cup was missing bearings.

I now have both ujoints of the rear drive shaft replaced with SPICER and had to also replace the outer seal of the rear driveshaft due, I believe, because of the ujoint failures and vibration.

We have an Excursion with a single piece rear drive shaft.

 

Here's my thread with pics and parts and the failed ujoint: https://www.ford-trucks.com/forums/1...oint-shot.html

Near the end I updated the thread to note I had to replace the NAPA ujoint after ONE YEAR. Probably still had a warranty, but I wasn't going to put another NAPA one in

Hope this helps!