Whining (electrical?) noise from differential

[er-minio]

Trying to understand if this is happening only to me or if it is a known issue or (hopefully) it's an issue related to the fake engine noise in the cabin.
Not a massive issue, as it happened just a few times in the last year or so.

Supra Pro 2.0, European spec. The LSD should be the mechanical one, not the electronic.
Very rarely and very randomly, when cruising at medium/low speeds (50 to 80mph) I do hear a whine coming from the rear of the car. It seems connected to the speed, but the whine seems more "electrical" than mechanical.
There are no vibrations, the car runs fine. Differential works.

I'm pretty sure I recorded a video of this last summer, I just have to find the file.

It did it first time when the car was about 15k miles, last time it happened was last month, a bit less than 30k miles.
Car is about 2 years old, I had it from new.


I suspect this very faint whine is produced by the rear speakers, and it might be a by-product of the fake engine noise. I haven't had a chance to deactivate it, but also the whine happened just a handful of times over the last two years.
Diff oil has been changed with the service this August and was ok.


Anyone experienced something similar, on both drivetrains?

Thanks.

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[itzTang]

check the fluids 1st step or just do the diff service and see if noise goes away.

 

[er-minio]

Diff service and fluids replace in August.
Had the sound just once since then.

 

[itzTang]

Diff service and fluids replace in August.
Had the sound just once since then.

How did the fluid look? Metal shavings or shiny?

 

[razorlab]

Unless you have the sport pack, your 2.0 has the same non-LSD open mechanical diff as the 2.0 here in the states. Sport pack in the EU gets the active LSD diff like the 3.0L gets.

 

[er-minio]

It does have it.
Regarding the type in Europe, at least Toyota's literature, they keep saying it's a mechanical/non active LSD. It's kinda confusing, I never really investigated too much.

Last time I was able to check the parts, from memory, same part # as the M2 (but I have no idea of the trims/options there).

Looking at it, it does have cooling fins at the back (and a sensor plugged in) and looks slightly different from those of some 2.0 I've seen pictures of (from the US) and still different from 3.0 (less fins). But it's just something I noticed watching a few videos and photos over time. But it can be just different revisions.

 

[er-minio]

How did the fluid look? Metal shavings or shiny?

Didn't do it myself, but mechanic said it was all perfectly good. No metal.

My impression is that the noise is more an electric whine than mechanical somehow. That's why I assumed it was coming from the active sound system.

 

[razorlab]

It does have it.
Regarding the type in Europe, at least Toyota's literature, they keep saying it's a mechanical/non active LSD. It's kinda confusing, I never really investigated too much.

Last time I was able to check the parts, from memory, same part # as the M2 (but I have no idea of the trims/options there).

Looking at it, it does have cooling fins at the back (and a sensor plugged in) and looks slightly different from those of some 2.0 I've seen pictures of (from the US) and still different from 3.0 (less fins). But it's just something I noticed watching a few videos and photos over time. But it can be just different revisions.

If it's not the active LSD from the 3.0, it's an open diff. Not from the M2. None of the M-lite/Supras have M diffs.

Which of these two does it look like?

 

[er-minio]

I counted the fins wrong apparently

Ok, never realised it was the full active one.
Car was easy to spin around, that was enough

> None of the M-lite/Supras have M diffs.

Ok! Didn't know.
Matching part number was shown in the VIN decoder, but to be fair the data provided by the decoder is not always accurate.

The ones I saw in pics and videos I mentioned above are these, I suspected these were the open ones:

 

[razorlab]

Yea that is the active LSD diff. Same as Supra 3.0 but you get the M-lite cover.

The second image I posted is the open diff. Also same as the one in your photo wearing the hoodie.

Full M diffs have the cover on the bottom, not the back like ours.

So now my question is, did the place put OEM fluid in your diff or something else?

 

[er-minio]

Thanks.

OEM as service was made at dealer.

Just to be clear, the weird sound came up once even before the diff was serviced for the first time.

 

[Subydude]

For the noise, does it show up at light throttle while cruising? Diff should be warmed up, at freeway speeds (the 50-80 mph you mention), and then vary the throttle small amounts at very light opening. If the whine shows up while on light throttle, but goes away when off throttle or at lower speeds than 50 mph, then it's likely some wear on the ring and pinion. The sound also generally goes away at heavier throttle, but the engine also drowns out the whine (usually). If the sound is not there at all when the diff is all the way warmed up, at freeway speeds, and on light throttle, then it's likely something else.

A fluid change can help the diff by thickening the fluid up which helps the excessive gear lash (where the whining comes from).

If it's really intermittent and only comes around once in a while then I wouldn't worry about it. If it gets worse as you go into summer you could try changing the diff fluid to something thicker like a 75-110 and see if it helps.

If it's electrical you can unplug the active sound module as a quick/free method to test the rear speakers.

 

[itzTang]

if u think its the ASD you can always code it off and see if the noise continues if so it isnt the ASD and you can code it back

 

[er-minio]

I'll have to stop and unplug the last time it happens.

For the record, the first time I heard the noise it was last year, summer. Cruising at probably 70, been driving for hours (and the day before) and the car and transmission was up to temperature.

Now that I think of it, other time it happened I was traveling too (long distance) similar scenario.

It is incredibly faint to be honest.

I'm not really worried, more curious.

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