[MPerry]

I have a small drive line vibration that I have been trying to troubleshoot.  I know vibrations are usually u-joints and I have been under the coach many times checking them and greasing them but they always seem ok. Then today while working on other projects I noticed the driveshaft looked "odd". On closer inspection I think the shaft is out of phase. I believe the yokes are supposed to mirror each other, but in the attached picture, and I am hoping someone cam confirm, the yokes are not on the same plane. I added a line to the photo that connects the lower bolts on the u-joints to try and convince myself they are actually out of phase. So here are my questions:

1) Does anyone else think the driveshaft is out of phase?
2) If out of phase can it be unbolted from the transmission (left side) slide off the splines, rotated and slide back on to correct phase?

[Richard]

Looks out of phase a bit in the picture. The angle is severe! The greater the angle the more pronounced out of phasing will be. I “think” you can unbolt from the tranny, pull the inner shaft out of the outer shaft, rotate one or splines, and reassemble. When you bolt it back up use nuts that will not vibrate loose.

[MPerry]

Thank you for the quick reply. The leveling system is at its max in the picture, so its much less then that at drive height.

[77newell]

If you start with the center of the knuckle on the right edge of the picture and then proceed down the casting seam to the center line of the torque tube, when you arrive at the knuckle on the left the extension of the line we've been drawing appears to pass well below the bearing circle, let alone being near its center. Sure looks to me that these joints are well out of phase. Pull it apart as described and line it up, ah yes silence on the drive.

[MPerry]

   
Just went out an aligned the driveshaft. Unbolted the flange on the transmission side and slide it off. Cleaned it looking for alignment marks but only found one on the axle side of the shaft. Rotated the shaft a couple splines so the ends are in phase, slide together and bolted it back to the transmission. The flange bolts are 3/8 grade 8 with lock nuts. Reinstalled and torqued to 35 ft/lbs.

I think this looks better.

I wont get the coach out for a test drive until next week.

[Guy]

Thank you for your input on this subject. I have had a vibration between 50-55 mph for quite some time. My drive shaft is also out of phase. I will  align mine. I have been searching for this vibration for quite some time. Thank you, and thank you Richard also. You guys are great !

[TGDianics]

Check this out: https://www.youtube.com/watch?v=Idk3BVDVHq4

[MPerry]

I have a couple hundred miles on the coach and putting the drive shaft in phase has made a huge difference. Under load you could really feel the change in shaft speed that is demonstrated in the video. Now its very smooth, even an highway speed the vibration from the rear is gone. I cant imagine how it got messed up in the first place but glad its fixed.