Interesting site,to say the least! Hopefully, someone has a solution to an annoying vibration in the driveline of my '03 GMC Sierra p/u trk. Problem started after hitting a major rain filled chuck hole on I-75 N in KY 6 wks. ago. Tires have been rebalanced and rotated. took the hit on the left side, F&R, at 70 MPH. Universals (3) and mid carrier replaced a yr. ago at 86K, now has 94K. Changed out F&R universals today with no success. Vehicle has vibration from 41-46 MPH constant. Above or below that range, no problem. Any ideas? Thanks for your input.