I have a 2003 Ford Excursion Eddie Bauer with the 6.0 and 4x4. I recently replaced the u-joints in the rear driveshaft after figuring out they were bad due to a drone noise at higher speeds and some vibration. The rear u-joint was toast as I couldn't get it to move at all when it was out and even took a lot of work with a press to get the u-joint apart. This is a 1 piece shaft with a slip towards the front part which moved fine while I had it out.

Now when driving from approx 56 mpg to 70 I have a vibration that can be felt through the vehicle. It is a vibration like you are driving over very shallow very close rumble strips. It is not in the steering wheel.

I am guessing my driveshaft may have either been damaged or lost a weight, got out of balance at some point when the u-joint was bad. I don't recall seeing a weight on it when I did the u-joints but it does have the large circle on the end by the rear. I made sure to mark how the flanges went on each end to ensure that was not an issue.

Is it possible a bad u-joint messed up my driveshaft? Kind of stumped on this issue. Thought about removing my rear driveshaft and taking it for a drive in 4x4 to see if anything changes but thought I would see what other ideas exist.

I did do a search and it seems like others with similar problems had their driveshaft re-balanced or replaced and probably 50% had a positive return.

 

I would take it to get rebalanced, had a similar situation in my F250 many moons ago.

Replaced u-joints and had a rumble from around 48-63 mph, all was good again after a shop balanced it.

 

other drive shaft issues ghat will cause a vibration.
1. worn slip joint , either the splinded male or female end.
2. not phased correctly during reassembly
3. lift kit added and not shimed correctly. out put and pinion need to be parallel.

a google search will show you how to measure the play in your slip joint.

ears on both ends must be sligned

need an angle finder to verify. if you have a lift kit post a pic of the rear springs and how they mount to the axle and i will go into detail

 

Not sure I understand what phasing is. This is my first driveshaft u joint replaced with a slip joint so perhaps I messed up. I usually just mark the ends and make sure they match going back on.

I do not have a lift kit on my EX so I can skip that.

I think I will just find a place to balance the shaft and make my life easier.

 

great if is out of balance but that isn't a common problem, more often it is the slip yoke either worn or needs grease.

 

Did some researching on phasing and determining what out of phase is. I will pull the driveshaft and give it a go. I guess moving the shaft around it could have come apart and got out of phase. Not sure how far it needs pulled to seperate but seems like an easy check before I take the driveshaft to a shop.

 

you can just look at it snd see if the ears are lined up.

 

I have the same problem. I have changed one joint because previous mechanic got one needle in the bottom of the cup instead of lined up like soldiers. Occasionally it would bind and make awful vibration/noise. I inspected the rear, fine.

Part of of my problem was putting the driveshaft flange 90’ out to the bolts originally used on transfer case.

First.. There was was a slight rust pattern from previous alignment and no the no longer bolted together flat.

Second... I had the flange bolts back out while driving because I used antisieze instead of locktite. Not fun. Took many hundreds of miles towing to show up. Diagnosed and tightened on the journey. However, I did not see at the time while the flange was flopping against the transfer case face it slightly deformed both flanges. When tightened down it flexed the driveshaft face and bound the u joint slightly.

I only found that by pulling the slip shaft apart and reinstalling the mating to torque and then moving the joint around. I could feel the binding. I then flap disc sanded the burs off and reassembled.

Still had a slight vibration.

Third... I have air bags. I inflated to 60 psi a couple weeks ago. Raised the rear 1”. The vibration is half of what it was. This changed the driveline angle. I am stock, no lift rear. Still wondering on this one.

Fourth.... there is a YouTube video on balancing driveshaft yourself with hose clamps. Jack stands, run truck in gear up to vibration speed. Mark drive shaft with steady hand and chalk on a stick. That’s the high spot. Place two clamps with screw opposing chalk mark. Check, move, repeat.

I am going to try this next

i appreciate any tips I see while reading your thread.

 

Apparently my lack of detail is what caused the issue. I found one cap on for the u-joint on the rear of the driveshaft not fully seated fully. I got it pushed in a little further and took it for a drive and vibration disappeared.

 

how did you get the clip in if it was not seated ?

 

It had a goofy clip cause its the cap that had the grease zirk in it and I didnt realize it wasnt fully seated. Lack of detail when distracted by 6 kids in the shop.