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Which alternator do I have?

Discussion in 'GM Electrical Tech' started by McClintoc, Oct 20, 2012.

  1. McClintoc

    McClintoc ɹoʇɐɹǝpoɯ Staff Member 2 Years 1000 Posts Platinum Contributor

    I have 2001 Silverado w/ the 4.8L V-8. How do I tell which alternator I have? Does anyone know how many amps the stock alternator has? If not, where do I look to find that info?
     
  2. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    That model shows a 145mm (5 3/4") diameter case (145amp output) and a 135mm (5 3/8") Diameter case (105 amp output) . So, I would say that you have to pull it off and measure it or when you go to buy a new one take yours with you and match up the sizes.
     
  3. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    Pikey, could he use the RPO codes on the glove box door? For example, my truck has a KG3 code which is the 145 amp alt.
     
  4. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts


    Good call [MENTION=54249]RayVoy[/MENTION] , I did not even think of that. He could use a vin decoder like http://www.compnine.com/vid.php
    and view all the rpo and options on his truck
     
    1 person likes this.
  5. McClintoc

    McClintoc ɹoʇɐɹǝpoɯ Staff Member 2 Years 1000 Posts Platinum Contributor

    Thanks for the link, Pikey! It worked. I typed in my VIN and it gave back a ton of information. It shows I have the 105 amp alternator.
     
  6. Pikey

    Pikey Moderator Staff Member 3 Years ROTM Winner 1000 Posts

    Glad to help
     
  7. McClintoc

    McClintoc ɹoʇɐɹǝpoɯ Staff Member 2 Years 1000 Posts Platinum Contributor

    I am still in need of replacing my alternator but, upon replacing it, I'd also like to upgrade it. I currently have the OE 105A alternator and would like to go to the 145A alternator. Is there any harm in making that big of a jump? Will there be any other electrical parts I'll need to change out as well or will it simply be just an alternator swap?
     
  8. j cat

    j cat Rockstar 4 Years 1000 Posts

    auto zone has the 105/145 amp both should fit. most use the 145. I replaced my 105 with a 105 but the larger should fit. also many do use the larger when they need replacing. If for some reason you do not like the fit just bring back and get the 105. looks like the 105 is more money. lifetime warranty. thats why I got new replacement at auto zone . was $140 a few years ago.
     
  9. McClintoc

    McClintoc ɹoʇɐɹǝpoɯ Staff Member 2 Years 1000 Posts Platinum Contributor

    I'm not too worried about the physical fit of the alternator. I'm more curious about the electrical fit - as in, is it going to hurt anything electrically if all I do is swap the 105A for the 145A alternator and nothing more?
     
  10. RayVoy

    RayVoy Well-Known Member 2 Years 1000 Posts

    No, it will only provide what is required. Just like installing a larger 12 volt battery, there is more power if required, but only when required.
     

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