04 Tahoe Alternator Ground?

[Z71Tahoe2004]

I've been watching videos on how to do the Big 3 upgrade to my ground and power wires under the hood. Noted that one of the Big 3 is a ground wire from the battery to the engine block, which many attach at the alternator. Also lots of videos recommending that the alternator be grounded from one of the alternator bolts (that holds it onto the alternator cradle) to the negative battery terminal.

I popped the hood this morning to take a look and noticed a 'GND' etched into the alternator cradle and pointing in the direction of the bolt. There is no ground cable anywhere on the alternator. I've had the truck for almost 15 years and realized I don't think there's ever been a ground wire for the alternator. Looked at the Haynes manual and no reference there, either.

I've had a slight whining sound on acceleration and deceleration for some time. Wondering if it would be fixed by adding a ground wire (1/0 gauge).

Anyone have any thoughts?

 

[Scottydoggs]

bolting the alt on is its ground, just like a starter. you can bolt your ground to the engine block where ever is a free spot in the clear.

 

[Z71Tahoe2004]

Thanks. Do you think adding a 1/0 gauge ground wire to the battery negative terminal would fix the whine?

 

[Doubeleive]

doing the big 3 may not help anything but it certainly couldn't hurt.

 

[mikeyss]

I replaced my alternator with a Napa one about 6 months ago, and it whines at lower speeds. I have 2 batteries setup. I think some alternators are just noisey?

 

[Doubeleive]

alternator whine would drive me crazy, I listen to my vehicles engine/drivetrain that's part of how I know when something isn't quite right

 

[mikeyss]

alternator whine would drive me crazy, I listen to my vehicles engine/drivetrain that's part of how I know when something isn't quite right

When I put the Napa alt on, it whined from day 1. I thought maybe it was electrical noise coming through the speakers at first, but have ruled that out. The volt gauge shows normal charging, however at times it's up way higher, close to the 3rd line on the gauge. I am on the fence of warranty it out for another one.

 

[Z71Tahoe2004]

I replaced my alternator with a Napa one about 6 months ago, and it whines at lower speeds. I have 2 batteries setup. I think some alternators are just noisey?

Might be the case. I recently discovered that the replacement alternator I got from O’Reilly was actually a 105 amp rather than the 145 amp the truck actually requires. That eventually caused a major whine. I called in the warranty and got a refurbished 145 amp from them and dropped it in. The whine went away for a week or two then returned at low speeds. I’m thinking about upgrading to a higher amp alternator (Mechman seems to be good) and putting in some 1/0 gauge wires. Hoping that’ll fix the whine as well as give the electrical system a boost and help with things like dimming headlights and interior lamps at startup.

 

[S33k3r]

Might be the case. I recently discovered that the replacement alternator I got from O’Reilly was actually a 105 amp rather than the 145 amp the truck actually requires. That eventually caused a major whine. I called in the warranty and got a refurbished 145 amp from them and dropped it in. The whine went away for a week or two then returned at low speeds. I’m thinking about upgrading to a higher amp alternator (Mechman seems to be good) and putting in some 1/0 gauge wires. Hoping that’ll fix the whine as well as give the electrical system a boost and help with things like dimming headlights and interior lamps at startup.

Out of curiosity, is it a physical whine, or one that comes through the electronics?

 

[Z71Tahoe2004]

Out of curiosity, is it a physical whine, or one that comes through the electronics?

It seems more like a physical whine. You can hear it coming from the engine area when you have the window down and it definitely shows up when you place a stethoscope on the alternator and press the accelerator.