One problem related to driveshaft has been reported for the 1998 Chevrolet Silverado. The most recently reported issues are listed below.
While down shifting the u-joints broke and driveshaft separated and fell onto the road. Vehicle was in 4-wheel drive when this occurred. Mechanic replaced both u-joints , added oil, and reinstalled the driveshaft. The problem recurred while shifting from 2nd to 3rd gear.