Roaring noise under load (1 Viewer)

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fan bearings?

Here's another noise thread: I've been getting a sorta roaring noise only under load, it's not a rumble, rattle, grinding, skraping, or high pitched whine. It's more like a moan or mild roar that gets louder directly proportional to road speed and only under load, it goes away as soon as I take my foot off the gas pedal. It starts out almost immediately as I accelerate away from a stop light for example and builds in tempo until around 30-40 mph, then seems to go away and comes back sounding a bit higher pitched at 50+ and just keeps getting louder the faster I go. It's not present in neutral at any road speed or when standing still and revving the engine, only under load and moving. My front driveshaft is out and the center diff is locked but the roaring noise was present before I did that and hasn't changed (I was also getting a vibration around 50mph so took out the DS to replace the U-joints). From reading other threads it sounds like it may be a bearing noise, question is which one, rear pinion maybe??

i had a similar noise a few years back. i thought it could be tranny related so i took it in after work to have the tranny fluid flushed & replaced.

As the guy is doing his thing under the vehicle, i'm checking things out under the hood as i usually do and i noticed that the fan wasn't sitting quite straight. I grabbed a hold of it and that thing was wobbling all over the place, the bearings were totally gone. i nursed it home and parked it until i had a new fan/clutch in place.

HTH,
Faron
 
@CJF @FaronF

I have 2009 LX570 with 121k miles which I acquired recently. Drives great. But I recently noticed a "roaring" noise when I accelerate +around 35-40 mile range. It almost feels like a droning roar (continuous hum) and it goes away after 50 mph. It comes the centre of the car under carriage.it feels like coming from the spindle that connects front and rear axles.

120k service is not done by the previous owner. On my last oil change / Multi point inspection, I was told the vehicle is us great condition. Lexus dealer did the pre purchase inspection and passed it. A reputed Lexus mechanic did the oil change and said everything looks good.

Do you think a 120k mile service would fix the roar? Can you tell me the questions to ask the technician?

Please advise,
 
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Alternator
 
How serious is this?
Was the issue we had on our 4Runner, your description fits what we had. The alternator wears out and the roar sounds vary with speed as the belt attached to the alternator moves at the rate the engine makes it go.
 
Hi,

I have my 2009 LX570 at the mechanic for 120k service. When I asked about Transmission flush, mechanic suggested not to do it unless I want him to do it. He suggested drain/refill. Do you think if any issues if I go for the tranny flush?

Appreciate your insight

Thanks and Have a great indepence day holiday!
 
Hi,

I have my 2009 LX570 at the mechanic for 120k service. When I asked about Transmission flush, mechanic suggested not to do it unless I want him to do it. He suggested drain/refill. Do you think if any issues if I go for the tranny flush?

Appreciate your insight

Thanks and Have a great indepence day holiday!
Typically you'll find everyone suggests drain/refill. Full flush to be done properly isn't a basic process and if you mess up, it's costly.
 

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