I would hate to keep on troubleshooting the oem shaft just to end up with a dc shaft anyway. Sucks cause i just replaced the u joints. My problems started after i regeared to 4.88 with 33 inch tires. Maybe because its spinning faster now. I just pulled the rear shaft and the grrr is gone. I may just follow your lead. Thanks.I just spent 2 years chasing mine with new u-joints (2x, once by me, then once at pro shop), balanced drive shaft, adjustable arms, etc etc. Just installed a DC rear shaft 2 or 3 weeks ago and finally vibe free.