Transmission whirling sound

[Fungus007]

I have a 2014 1.33l 6 speed iq. 

Whenever I accelerate in any gear between 80-85kmh in any gear I can hear this faint whirling sound coming from the centre console which I’m guessing is where the transmission is. Outside the aforementioned speed no noise can be heard. 

I’ve ruled out a bad wheel bearings cos the sound goes away as soon as I put the car in neutral and let the car coast or depress the clutch. 
 

I got my mechanic to take it for a test drive and he said it was perfect fine. He said he could even hear the noise but at a different frequency below 80kmh but it so happens the frequency I can only detect is at 80-85km/h. 
 

I don’t really believe this cos I know the age impacts on what frequently a human can hear and cos I’m in my 30s i could think a large majority of iq owners would fall within this age group yet I don’t hear any complaints. 
 

I’ve been trying to self diagnose the issue and came across this video where they show a noise of a car with bad pinion gears which so happens to be exactly the same whirl I hear on my iq. 

https://youtu.be/Awbk1kPydX4?si=SuaQQmyeM3ilBsOG

Although not an iq this car makes a similar whirling sound 

https://youtu.be/Uayr9nREpFM?si=6xQYY4YVe4EMZ_Iy

 

 

 

 

 

 

 

 

[Fungus007]

Anyone? 

[APS]

It sounds like gearbox whine. The first thing I would do would be to change oil in the gearbox. The aim here is to look at the condition of the old oil and the amount of metal on the magnetic drain plug. There will always be some glitter in the oil and metal on the plug, but you want to see if there is more than normal. How much is that? Well, hard to describe. Take photos and/or get a mechanic you trust to do it. They should be able to give you a second opinion on it. 

If the gearbox is indeed faulty, you can either get it rebuilt or replace it with a good second hand ditto. Or live with the noise until it gets unbearable or malfunctions. Depending on the type of fault and how you drive it, it may last for years.

[Fungus007]

1 hour ago, APS said:

If the gearbox is indeed faulty, you can either get it rebuilt or replace it with a good second hand ditto. Or live with the noise until it gets unbearable or malfunctions. Depending on the type of fault and how you drive it, it may last for years.

But the car has only done 100,000km so even if the transmission fluid was never changed when new it shouldn’t cause premature wear especially when it’s a manual not the cvt?

 

If the sound doesn’t get worse the longer I drive I can say for sure it’s not a worn internal transmission bearing right or something related to the drive train? 

Getting the gearbox rebuilt is difficult as all the iqs here are grey imports. 

If its not a gearbox related issue what else do you think it could most likely be? 
 

The whine is completely speed rated and only can be heard between going at 80-85kmh regardless of which gear I’m in. 
 

 

[APS]

12 minutes ago, Fungus007 said:

But the car has only done 100,000km so even if the transmission fluid was never changed when new it shouldn’t cause premature wear especially when it’s a manual not the cvt?

The gearbox oil will most like never have been changed, and it shouldn't need to be. But in order to diagnose the problem, the easiest course of action is to drain the existing oil, analyse it. Getting new oil in the box will not do any harm. 

You are right, manual gearboxes, due to their relative simplicity, do not normally cause trouble until perhaps when you reach very high mileage. But low mileage failures are not unheard of. Do you know the history of the car? Have you had it since new?

 

15 minutes ago, Fungus007 said:

If its not a gearbox related issue what else do you think it could most likely be? 
 

The whine is completely speed rated and only can be heard between going at 80-85kmh regardless of which gear I’m in. 

It is most likely the gearbox. Only tyres, drive shafts, or wheel bearings would be speed dependent in that way. But those do not cause high pitched whine and the fact that the noise is dependant on load also points to the gearbox. 

19 minutes ago, Fungus007 said:

Getting the gearbox rebuilt is difficult as all the iqs here are grey imports. 

Gearboxes tend to use many off the shelf parts. You'd be surprised how many parts are shared between gearbox models. Ever gearboxes are used across many models. The IQ is a bit different as it required some serious repackaging of components due to its miniscule size. It is still very possible that Toyota used standard components. In fact, Toyota will try to reuse as many parts as possible as it significantly reduces manufacturing costs. 

[APS]

I should have said that the fact that the whining doesn't change pitch with different gears (?) points to the final drive as in the video you shared. 

[Fungus007]

5 hours ago, APS said:

I should have said that the fact that the whining doesn't change pitch with different gears (?) points to the final drive as in the video you shared. 

No it the whine doesn’t change pitch regardless of which gear I’m in within  80-

 

5 hours ago, APS said:

It is most likely the gearbox. Only tyres, drive shafts, or wheel bearings would be speed dependent in that way. But those do not cause high pitched whine and the fact that the noise is dependant on load also points to the gearbox. 

Gearboxes tend to use many off the shelf parts. You'd be surprised how many parts are shared between gearbox models. Ever gearboxes are used across many models. The IQ is a bit different as it required some serious repackaging of components due to its miniscule size. It is still very possible that Toyota used standard components. In fact, Toyota will try to reuse as many parts as possible as it significantly reduces manufacturing costs. 

What about the input bearing on the differential? It’s sounds similar to the videos I’m uploaded with the post and the symptoms only occur under laid like mine? 

[APS]

5 minutes ago, Fungus007 said:

What about the input bearing on the differential? It’s sounds similar to the videos I’m uploaded with the post and the symptoms only occur under laid like mine? 

 I have not distinguished between gearbox and differential as they are part of the same unit. It could be the output shaft from the gearbox to the differential. But bearings rumble more than whine. Whining is typical of gear teeth impact. Compare the noise to the typical whining you get in reverse gear. It's more similar to that, I would say. 

In any case, as I mentioned, there is no harm in replacing the gearbox oil. If that looks bad it would confirm something is not quite right. 

[Fungus007]

I spoke to my other mechanic and he said taking a fluid analysis will not be accurate as there's no guarantee the

sample taken will have any metal particulars to tell if there's any damage

[Fungus007]

3 hours ago, APS said:

 I have not distinguished between gearbox and differential as they are part of the same unit. It could be the output shaft from the gearbox to the differential. But bearings rumble more than whine. Whining is typical of gear teeth impact. Compare the noise to the typical whining you get in reverse gear. It's more similar to that, I would say. 

In any case, as I mentioned, there is no harm in replacing the gearbox oil. If that looks bad it would confirm something is not quite right. 

What is the recommended gearbox oil from Toyota? Is there any way to check the oil level? 

[APS]

The Owner's Manual states 2.4 litre of 75w, GL-4

A normal 75w90 will do. Keep it to GL-4 and not GL-5

Note from the manual:

Quote

Please be aware that depending on the particular characteristics of the gear
oil used or the operating conditions, idle sound, shift feeling and/or fuel effi-
ciency may be different or affected. Toyota recommends to use “TOYOTA
Genuine Manual Transmission Gear Oil LV” to achieve optimal performance.

The manual does not include instructions for checking transmission oil level. In general there are normally two plugs on Toyota transmissions, a drain plug and a fill plug. Located on the differential housing.  The IQ transmission has the differential on the front.

With the car on level ground or jacked up level, the oil should be up to the bottom of the filler plug hole. 

• Replacing the oil is as simple as, with the gearbox warm, removing the filler and then the drain plug. Let the oil drain.
• Clean the drain plug and reinstall it (ideally with a new seal).
• Then fill new oil through the filler hole until it starts to overflow through the hole.
• Reinstall filler plug.

Again, this is not specific to the IQ. But chances are very high it is the same. 

[Antonio2]

Hi

Reference the gearbox oil change. Just a couple of tips.

BEFORE removing the gear box drain plug ALWAYS remove the filler plug (24mm) FIRST.

If you drain the gear oil out first, and then have problems removing the filler plug (which was VERY tight on my IQ) - you could find yourself with no oil in the gearbox, and no way of refilling it should you need to revert to a "plan B". 

Also the standard Toyota 24mm hex filler plug has rounded "corners". So to avoid any "mishaps" when removing it - it is better to use a good hex socket, rather than a 12 point socket type. Using a 12 point socket will increase the risk of rounding the corners of the  "awkward to get at" filler plug".

[Fungus007]

On 10/15/2024 at 1:32 AM, APS said:

The gearbox oil will most like never have been changed, and it shouldn't need to be. But in order to diagnose the problem, the easiest course of action is to drain the existing oil, analyse it. Getting new oil in the box will not do any harm. 

You are right, manual gearboxes, due to their relative simplicity, do not normally cause trouble until perhaps when you reach very high mileage. But low mileage failures are not unheard of. Do you know the history of the car? Have you had it since new?

Gearboxes tend to use many off the shelf parts. You'd be surprised how many parts are shared between gearbox models. Ever gearboxes are used across many models. 

All the mechanic's I've spoken to said getting an oil sample will not mean anything as most of the metal filing will be caught on the magnet filters 

No I do not know of the history of the car but the engine and body is in great shape. 

Is it possible to buy a rebuild kit with the all the bearing and gears in japan? 

 

[Fungus007]

14 hours ago, Antonio2 said:

Hi

Reference the gearbox oil change. Just a couple of tips.

BEFORE removing the gear box drain plug ALWAYS remove the filler plug (24mm) FIRST.

If you drain the gear oil out first, and then have problems removing the filler plug (which was VERY tight on my IQ) - you could find yourself with no oil in the gearbox, and no way of refilling it should you need to revert to a "plan B". 

Also the standard Toyota 24mm hex filler plug has rounded "corners". So to avoid any "mishaps" when removing it - it is better to use a good hex socket, rather than a 12 point socket type. Using a 12 point socket will increase the risk of rounding the corners of the  "awkward to get at" filler plug".

All the mechanics I've spoken to have said if it really is a worn bearing in the gearbox changing the fluid will not fix anything and if it does it will only a temporally time before the sound shows up again. Reason being the oil is the prevent parts from damage and if the bearing is already causing sound its too far gone and needs to be replaced. Also if i were to replace the oil and it doesn't' fix the whirling sound I'd need to take it out which would be a huge waste of money as the oil wont ever be used again. 

[APS]

I've tried to help you diagnose the problem. Replacing the oil is not fixing the problem, it is just one step to confirm a diagnosis and make sure you know the state of the oil. As I've said, it will do no harm. At the moment, you don't even know if you have any oil there. The cost of two litre of oil is small compared to removing and rebuilding the gearbox.

Alternatively, you can go ahead and assume the gearbox is faulty and get it repaired or replaced.