A Ford Excursion is a full-sized SUV, produced from 2000 through 2005. An Excursion that develops vibrations might make you think of tire or brake problems. The drive shaft can also cause the SUV to vibrate.
The drive-shaft balancing weights, while typically welded on, are susceptible to impact. Hitting something hard enough with your drive shaft might cause the weights to fall off, leading to an imbalanced drive shaft and vibration.
Dents or bends in the body of the Excursion's drive shaft can cause a vibration. The vibration increases with the size of the dent or bend.
Universal joints connect the drive shaft to the transmission and the differential. U-joints sometimes loosen and cause a vibration in the drive shaft.
The only way to rectify loose U-joints is to replace them. A drive shaft with a dent large enough to create a vibration must be replaced as a whole. A dealership -- or a drive-shaft specialist --can re-balance the drive shaft.
