Isuzus DO NOT like box store brand alternators. If they work at all they will die in a few months. Bosch and Napa Gold are the ones most others have found to work well. Starters arent much different when it comes to box store ones. Replaced the starter on my nieces toyota once. Went through every starter on the shelf at Checker and Autozone. They all tested fine on the test bench but I only managed to find one that would even crank (not even in the vehicle) with a brand new 750 amp battery. Had to hook them up with jumper cables in their parking lot to prove to them their starters were crap.