One problem related to differential unit has been reported for the 2003 Chevrolet S10. The most recently reported issues are listed below.
Had driveline howl/vibration since vehicle has been new between 45-70mph. Dealer has put in 2 new rear axle assemblies and have not been able to fix problem. Third time I brought vehicle into dealer for same problem the said noise was normal for the 03 model year s-10 pickups. I put on new rims and tires to see if that could be the cause, problem still there. I now have 18,000 miles and noise and vibration is getting worse and worse and vehicle is currently at another dealer to whom I did not purchase the vehicle from to fix the problem but they can't find anything wrong.