vibration

wjajr said
So what you are saying is that both welded ends that receive a U joint have to be orientated the same. I have to assume this is the way a factory shaft would have been built.

The rear joint can only be installed in two positions to the pinion at a 180 degrees difference; can there be a benefit to one or the other position?

Front yoke installation; can there be a sweet spot depending on the multiple positions one can slide it into the transmission?

Im asking this, as my car, and previous Dart as well as my AWD 300C have exhibited a slight rolling vibration in the 60 to 70 mph range that oscillates in intensity at constant speed. I have always wondered if this is a combination of slight drive line imbalances coupled with tire balance issues that as the parts rotate the combined differences line up creating a perfect out of balance combination at some point that comes and goes. Sort of like when all the planets line up after so many orbits around the sun if you get my drift.

Yes the weld yokes must be in the same plane, if they aren't then something is tweaked or twisted, or it's a older theory of the pressed tube into tube with rubber found in some older chryslers and some fords and buicks and caddys.

The slip yoke has to stay on the shaft the same orentation it was originally balanced at or it is no longer in balance, same holds true for flange yokes and cv shafts with h yokes and centering flanges.

As for the 300, they use flex couplers or flex discs they can develop issues and cause some of the drowning style vibrations you're experiencing, or it could be the center bearing or the rzeppa or joint depending on which shaft that 300 has or the shaft can have lost a weight or it developed a new harmonic and needs balancing.