One problem related to driveshaft has been reported for the 2002 Nissan Frontier. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2002 Nissan Frontier based on all problems reported for the 2002 Frontier.
Entire vehicle vibrates at various speeds, vibration coming from under seat area of cab source is probably center carrier bearing of drive shaft. Dealer replaced driveshaft at 156miles after confirming problem on test drive. But still has vibration dealer made another attempt at repair then on third time in shop said it was normal. I filed under FL lemon law and manufacturer replaced all 4 tires. But truck still has vibration, it is now much more severe at 13000 miles and I aam still pursuing repurchase under FL lemon law. I think you should investigate this defect as I have first hand knowledge of another truck where the carrier failed such that the repairing dealer told the owner that he shouldnt drive his truck until the bearing was replaced because it could cause an accident. His truck was repurchased by Nissan.