How do I tell if I have the 105Amp or 130Amp setup on my truck to get new belts? I wanna get new belts for summer road trips and keep the old ones as backup if needed. Which to choose? I have the Chev 5.3L and 3.42 diff. Any help appreciated.
Is there a part number on your belt? Or, can you take if off and go to the parts store? It is a great idea to change the belt and keep the old belt behind the seat. You can be pretty sure that it will fit, if sometime in the future you need it.
Go to a parts site like acdelco.com or rockauto.com and look up an alternator for your truck. This'll include amp ratings and hopefully a picture.
I suspect one alternator has a bigger pulley than the other.
Also you RPO codes in your glovebox can be decoded (Google RPO Decoder) to find out if you have a heavy duty charging system. If you have shorter rear gears than normal you might have a factory tow package that includes the bigger alt for example.