2005 GX470 here. Owned for 8 years and has been a great vehicle. Had the alternator replaced in September and since then it’s been doing this weird buzzing noise on acceleration. It’s hard to describe but I attached a video. Lexus dealer has had it 2 weeks and they can’t figure it out. Hoping someone has some insight here. Alternator is charging, battery is new. All pulleys and accessories are operating as normal.

 

I'm not able to pick out the buzzing, when is it happening exactly (time stamp)? Is this a good video for the noise you're trying to show?

 

it starts at 5 seconds into the video. Almost sounds like an electrical noise, like I said very hard to describe

 

Only on hard acceleration, or also regular acceleration? Does it correlate to 2nd or 3rd gear, or any other consistency you can identify?

 

Seems to mostly happen during the first 15-20 minutes of driving. Happens above 2500 RPM for the most part. Mostly in 2nd gear but I can hear it faintly at idle in park sometime. It’s so weird and had the dealer stumped for 2 weeks. They found no issues. Runs like new drives like new. No transmission slips or performance issues. Just that noise. I personally think it’s a bad alternator bearing but it’s still charging fine so they won’t warranty it