97 Sub K2500 / alternator problem

Hi, I changed my alternator a few weeks ago, after shaking ==> bearing. After changing is a loud noise on the alternator. It's sounds like a turbo charger. Have any an idea, what that is? It bothers me and I have to drive 5000 miles next month. Thanks for any help :)

Hi, I changed my alternator a few weeks ago, after shaking ==> bearing. After changing is a loud noise on the alternator. It's sounds like a turbo charger. Have any an idea, what that is? It bothers me and I have to drive 5000 miles next month. Thanks for any help :)


I would exchange the alternator. The noise you are describing could possibly be a bad diode in the alternator.

Thanks for the tip, but I did change the alternator 3 weeks ago, 2 weeks ago, it began to make noise again (same noise as the old alternator), today the noise got more and a little bit a shake. That sound's like a turbocharger. When the AC turn on it's quite for a few second. Then it begins again. I don't have knowladge about the 454, I moved from Switzerland to the US last year, you may see it on my english :lol2:

You know it may actually be the belt or possibly the tensioner that is causing the sound, Try some belt dressing and if it gets quiet the thats probably what it is

Thanks for the tip, but I did change the alternator 3 weeks ago, 2 weeks ago, it began to make noise again (same noise as the old alternator), today the noise got more and a little bit a shake. That sound's like a turbocharger. When the AC turn on it's quite for a few second. Then it begins again. I don't have knowladge about the 454, I moved from Switzerland to the US last year, you may see it on my english :lol2:


I realize you changed the alternator, But when they remanufacture them they only test the diodes and don't replace them. sometimes they go out right away and they will make the alternator growl/ howl, But will still charge just not full output. I would try what GMCmudbogger suggested to make sure it is not the belt or the tensioner. It could also be a bearing if they didn't get it in straight and then forced it back together. I have had multiple alternators go bad right ofter purchasing and some were bad when installed. The alternator should still be under warranty so you would have nothing to lose, But a little time.

Thanks for the tip, but I did change the alternator 3 weeks ago, 2 weeks ago, it began to make noise again (same noise as the old alternator), today the noise got more and a little bit a shake. That sound's like a turbocharger. When the AC turn on it's quite for a few second. Then it begins again. I don't have knowladge about the 454, I moved from Switzerland to the US last year, you may see it on my english :lol2:
Hi GMCMudBogger and Thunderbolt
I checked the pullies, and I figured out, that the pully between alternator and A/C is bad, so I tries the belt dressing a few times on a day, since then I have no problems anymore, no sound and fibriation. Than you verry much for the tip, sometimes is just a little thing, that make you a big trouble, if I would go in a shop to fix it, there change quick the alternator and the problem is still there, I appriciate for help. Have a great time, Volker