Hello,
I have a 03 F-250 4WD Supercab 5.4L. After working on the driveshaft I now had a noticeable vibration once I get up to 20-30 MPH or so. At highway speed I think it's also there but it's harder to tell because of normal road vibrations.
It all started when I had a grinding sound when driving and found the center support bearing to be the cause. Not wanting to fool with pressing the bearing off and new one back on myself without the proper equipment I took the front half of the driveshaft with the bearing and u-joint yoke still attached, to a local auto parts store that also has a full service automotive machine shop and had them replace the bearing. Before taking anything apart I marked the relationship of the front driveshaft flange to the transfer case and the yoke at the rear of the front half to the yoke on the front of the rear half. I also re-greased the slip yoke while I was at it and also marked the relationship of the two parts before taking it apart. Now that I have this vibration I went back and made sure I lined everything up just as it was and all looked correct. Now I'm wondering if the machine shop may not have been careful to mark the parts when they took the yoke off to replace the bearing?
What say you? After fooling around with the slip yoke that I re-greased I found that it only fits one way. Could that also be the case with the yoke on the front 1/2 shaft or do you really have to be careful when removing/ installing it? If the shop didn't mark the yoke to the shaft all the match marks I made aren't worth anything.

Thanks for any and all help!!

 

Did you replace the u-bolts on the universal joints? I had the same problem after I replaced my u-joints. The u-bolts seemed ok but I still had a vibration problem until I put new u-bolts on. I guess the vibration from the bad joint streched the old one's out. They seemed to be ok but they allowed the u-joint to move around under a load. Set your brake and put it in neutral then get under it and see if you can move it around in the yoke at all.

 

alignment on the transmission splines won't matter. There may or may not be a master spline there, but it isn't necessary.

On a two piece shaft, there will be a master spline that dictates the alignment of the two shafts together, this is to make sure the u-joints are in correct alignment with one another. There are then only two ways the shafts can connect to the pinion yoke. Either one is fine.

Is there any indication that they knocked a counterweight off of the shaft during the bearing R&R? If so, the shaft needs to be balanced again.

Is there any indication they ever squeezed either shaft in a vise? If so, the shaft is junk and needs to be replaced.

Is the bearing seated completely? If not, you might be able to get it to seat with a hammer, a punch, and about a hundred small taps.

Is the rear u-joint seated correctly? If not, you can loosen the bolts and make sure it stays centered when you tighten it... If this is a problem, there is something else wrong, as the u-joint is either seated or not... there really is no in-between.

 

Thanks guys. We might be talking about two different things here. On my truck there is the center support bearing and just behind the bearing toward the rear of the truck there is a yoke where the universal for the rear half of the driveshaft connects. So to get the center support bearing off, this yoke I am talking about would need to be removed first. There is like a 1 1/4 or 1 5/16 hex nut and then I'm assuming the yoke slips off which I'm also assuming is on a spline of some sort. I guessing the yoke may not have been reinstalled back in its original orientation by the shop that changed the bearing.

The drive shaft looks good I don't think the shop knocked off a counter weight or squeezed it in a vise. I also tried to spin the bearing on the shaft to see if it had any runout and it looked good.

The universal joints and u-bolts all look good but maybe tomorrow I will have time to try and put some load on it like rmeadows suggested. I made sure everything was clean and free of rust and dirt at the critical mounting surfaces before I re-assembled anything.


Thanks again!!

 

no, we're talking about the same thing...

that slip shaft has a master spline on it. It will only go back on one (possibly two) way. which is to keep the orientation of the u-joints correct. (for more information google "u-joint alignment")