Chevy Avalanche Fan Club Forum

CAFCNA Discussion => Buyer Questions & Answers => Topic started by: puddingpop on 09/13/18 06:22 PM

Title: Slight Hum/Whine With Gas On, Gone With Gas Off.
Post by: puddingpop on 09/13/18 06:22 PM
Hi, everyone,

I'm new here and have a deposit on a very clean 2007 LT with 170k and the heavy-duty rear locking differential.

On a test drive before and after the rear differential fluid was replaced, I noted a slight but perceptible hum or whine that sounds as though it's coming from the rear of the Avalanche. The hum is obvious while the accelerator is pressed and truck's moving at a steady speed. It goes away immediately when lifting off the accelerator.

The hum always occurs at highway speeds. I don't recall being able to reproduce the hum at speeds below, say, 40.

From what I've been able to find -- here and elsewhere on the web -- regarding a noise like that is not encouraging.  I'm hoping someone can give me some insight into whether or not I need to move along to a different Avalanche.
Title: Re: Slight Hum/Whine With Gas On, Gone With Gas Off.
Post by: MS03 2500 on 09/13/18 08:09 PM
I would not necessary say it's a deal breaker, from your description it sounds like a pinion bearing.
It depends on how bad it is. If its just the bearing I think it's about 700 if the bearing metal has gotten into gears you may have to replace the differential.

So call a couple of places for local pricing
Title: Re: Slight Hum/Whine With Gas On, Gone With Gas Off.
Post by: puddingpop on 09/14/18 05:24 AM
from your description it sounds like a pinion bearing.

Thanks for the suggestion. I'll look into it.