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Old 18th March 2012, 11:51   #76
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Default Re: How often should we change gear oil?

^^^Not really. Since "thickness" (I assume you mean thick and not fat) is usually related to viscosity, they may be no different. The SAE numbers for engine oils do not correspond to the numbers on transmission oils. In other words the average transmission oil may not be any more viscous than the average engine oil despite the SAE grades you see on the pack.

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Old 18th March 2012, 12:47   #77
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Default Re: How often should we change gear oil?

Gear oil change is mostly milage based as it lubricates and does not collect combustion impurities. At the most the oil collects the metal shavings resulting from aggressive gear changes. Many fleet owners simply filter the old gear oil, dewater it if required and reuse it. Some high end gear oil have graphite powder added to enhance lubrication under heavy load, but other wise it is plain viscous lubricant, which if not exposed to air and heat rarely decomposes.
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Old 18th March 2012, 19:32   #78
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Default Re: How often should we change gear oil?

Isn't the gear oil supposed to break down owing to the strong shearing forces it experiences in a gearbox? I ask because I do find a lot of manufacturers still recommending a gear oil change after a certain mileage or period.

In fact, I have been quite fascinated about how Ford claims that their gear oil lasts the lifetime of a car especially since the term "lifetime" is subjective & may vary, apart from the fact that I also believe that any sort of gear oil would also undergo degradation.

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Gear oil change is mostly milage based as it lubricates and does not collect combustion impurities. At the most the oil collects the metal shavings resulting from aggressive gear changes. Many fleet owners simply filter the old gear oil, dewater it if required and reuse it. Some high end gear oil have graphite powder added to enhance lubrication under heavy load, but other wise it is plain viscous lubricant, which if not exposed to air and heat rarely decomposes.

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Old 18th March 2012, 20:38   #79
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Default Re: How often should we change gear oil?

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Originally Posted by blackfire_9 View Post

In fact, I have been quite fascinated about how Ford claims that their gear oil lasts the lifetime of a car especially since the term "lifetime" is subjective & may vary, apart from the fact that I also believe that any sort of gear oil would also undergo degradation.

Thank god I was not dreaming, Ford really does tell that the Gearbox is sealed for life , I checked and it is filled with Synthetic 75w90 from the factory. But i am changing it anyways. What is the price of 75w90.
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Old 18th March 2012, 20:45   #80
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Default Re: How often should we change gear oil?

^^^Are you sure you want to fix whats not broken? If Ford is claiming what you said, I'd not touch it if I were you.... at least not unless I find credible reports that doing the contrary is somehow beneficial.
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Old 18th March 2012, 21:04   #81
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Default Re: How often should we change gear oil?

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Thank god I was not dreaming, Ford really does tell that the Gearbox is sealed for life , I checked and it is filled with Synthetic 75w90 from the factory. But i am changing it anyways. What is the price of 75w90.
Why not get it changed from the A.S.S itself?

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^^^Are you sure you want to fix whats not broken? If Ford is claiming what you said, I'd not touch it if I were you.... at least not unless I find credible reports that doing the contrary is somehow beneficial.
Changing an oil earlier than what's recommended wouldn't harm, I am sure. The only harm that could come of out it could be the carelessness in tightening the drain nut using a wrong torque. And Ford seems to be recommending ridiculous change intervals just to try & change the image of being a maintenance intensive brand.

In fact, this is precisely why they have stopped doing oil changes for the Figo until 10K kms, including the first oil change which used to happen at about 1500 kms in even Swift D (if I remember correctly). I have not heard of any other cars following the same regime. I am not sure if it's alright (first oil change at 10K) but I can vouch that changing the oil earlier won't harm.

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Old 18th March 2012, 22:15   #82
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Default Re: How often should we change gear oil?

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Originally Posted by Raccoon View Post
^^^Not really. Since "thickness" (I assume you mean thick and not fat) is usually related to viscosity, they may be no different. The SAE numbers for engine oils do not correspond to the numbers on transmission oils. In other words the average transmission oil may not be any more viscous than the average engine oil despite the SAE grades you see on the pack.
Sorry for the half baked sentence, yes I meant thicker; higher viscosity.
Gear oil made specifically for transmissions, transfer cases, and differentials in automobiles, trucks, and other machinery has higher viscosity to better protect the gears and usually is associated with a strong sulfur smell. The high viscosity ensures transfer of lubricant throughout the gear train. This is necessary since the devices needing this heavy oil do not have pumps for transferring the oil with only a portion of the lowermost gears bathed in an oil sump. This heavy oil can create viscous drag leading to inefficiencies in vehicle operation. Some modern automatic transaxles (integrated transmission and differential) do not use heavy oil at all but lubricate with the lower viscosity hydraulic fluid, which is available at pressure within the automatic transmission.
Most lubricants for manual gearboxes and differentials are hypoid gear oils. These contain extreme pressure (EP) additives and antiwear additives to cope with the sliding action of hypoid bevel gears.
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Old 19th March 2012, 00:59   #83
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Default Re: How often should we change gear oil?

^^^See the chart below please. As you can see, a 90 tranny oil is roughly as viscous as a 40 engine oil at around 16 centistokes. The world of lubes is kinda deceptive.

Name:  Oil grades.JPG
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Why not get it changed from the A.S.S itself?



Changing an oil earlier than what's recommended wouldn't harm, I am sure. The only harm that could come of out it could be the carelessness in tightening the drain nut using a wrong torque. And Ford seems to be recommending ridiculous change intervals just to try & change the image of being a maintenance intensive brand.

In fact, this is precisely why they have stopped doing oil changes for the Figo until 10K kms, including the first oil change which used to happen at about 1500 kms in even Swift D (if I remember correctly). I have not heard of any other cars following the same regime. I am not sure if it's alright (first oil change at 10K) but I can vouch that changing the oil earlier won't harm.
Well, you never know. Besides over torqueing and overthreading the nut, which is not beyound the expertise of our mechanics, there is chance of contamination. I'v seen them do this in workshops, and mechs are generally beyond bothering about such things. Also, can you be sure if what you are putting in is exactly what is inside? Of if mixing the new stuff won't cause any harm? Well, that said, the outcome may not be something dramatic, but the benefits are questionable. All you may achieve could be just waste of some good oil (not the best thing ecologically too, eh?)and other expenses towards labor and time. Anyway, its upto you.

Last edited by Raccoon : 19th March 2012 at 01:12.
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Old 19th March 2012, 08:34   #84
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Default Re: How often should we change gear oil?

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^^^
Attachment 904584
All you may achieve could be just waste of some good oil (not the best thing ecologically too, eh?)and other expenses towards labor and time. Anyway, its upto you.
How do we or can we tell if the gear oil is bad , I remember older cars had a dip stick for the gear oil. I do not even see a filling point for mine.
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Old 19th March 2012, 11:13   #85
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Default Re: How often should we change gear oil?

Well, one can refer to the service manuals to see the specifications of the gear oil being used in a said vehicle. Assuming that Ford's service manual may not list the specifications of the gear oil being used because of their claim (highly unlikely), I believe this piece of information can be had from the company.

And then just like we (enthusiasts) make it a point to know which oil an A.S.S is gonna use for the engine, we could most definitely do this little exercise for the gear oil as well & go ahead with the change only if the new oil to be used meets the standard specifications.

But like I have mentioned before, I would really like to know what magical stuff Ford uses in their gearboxes for such a claim or if the gearbox design is different in a way that the rate of degeneration of the oil is much less.

Nevertheless, I agree that it's a personal call on when you want to change the various fluids in your car.

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Also, can you be sure if what you are putting in is exactly what is inside? Of if mixing the new stuff won't cause any harm? Well, that said, the outcome may not be something dramatic, but the benefits are questionable.
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Old 19th March 2012, 12:00   #86
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Default Re: How often should we change gear oil?

Two things.

1. About the shear inherent in any hypoid gear set, this is why I stated if it calls for EP (for Extreme Pressure) then make sure you use EP oil.
@blackfilre_9; You can fool around with many fo the fluids, but be careful with the brake fluid (it is hygroscopic, so collects moisture, and tends to polymerise in the brake cylinders) and the coolant (in 95% of India it serves more as an water pump lubricant, and anti corrosion). Some may recall the water pump in a FIAT failing every two years or so.
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Old 19th March 2012, 15:35   #87
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Default Re: How often should we change gear oil?

^^^Quite so. But I'v always observed that they always handle brake fluid just like any other fluid at the workshop. They'll even leave the lid open for any amount of time. I doubt they even know that its so hygroscopic. Scary!

What might be the reason for the water pump to fail every 2 years in Fiats? And what might be the reason that they don't fail anywhere close to that often in today's cars? No idea about Fiats, as they were nowhere in the picture when I got on the car scene. Just curious to know. I just recall parents/relatives fuming how they needed to fill water in the middle of the journey because of a fuming engine, etc. And thats something we never need to do today.
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Old 19th March 2012, 17:27   #88
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Default Re: How often should we change gear oil?

Thanks for the tip, sir!

Well, I believe it's best if a consumer is a little pro-active because most often than not, the SC guys are one of the least educated bunch on such affairs.

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@blackfilre_9; You can fool around with many fo the fluids, but be careful with the brake fluid (it is hygroscopic, so collects moisture, and tends to polymerise in the brake cylinders) and the coolant (in 95% of India it serves more as an water pump lubricant, and anti corrosion). Some may recall the water pump in a FIAT failing every two years or so.
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Old 20th March 2012, 10:22   #89
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Default Re: How often should we change gear oil?

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What might be the reason for the water pump to fail every 2 years in Fiats? And what might be the reason that they don't fail anywhere close to that often in today's cars? No idea about Fiats, as they were nowhere in the picture when I got on the car scene. Just curious to know. I just recall parents/relatives fuming how they needed to fill water in the middle of the journey because of a fuming engine, etc. And thats something we never need to do today.
There were two common points of failure - a bust bearing or a bust water seal. I even had the former in my 118NE so could have been a Premier problem. One reason was the use of tap water. It will lead to corrosion. The muck will in turn wear out the bearing and / or the water seal. Also, the issue of messed up radiators was again because of blocked tubes, and poor or missing radiator caps. Modern cars have far smaller radiators but the combination of coolant, and pressure caps sees to the problem being non-existent. Also, the hoses will fail and partially block the water passage.

The only time I had a boiling radiator was when the Water Pump of my Amby failed. Yes, when you went up a hill a stop about half way was almost mandatory (Bhatta on Dehradun Mussorie) and (Jeolikot on Kathgodam-Nainital). I went up to Nainital many times (incl. 4up in my Padmini DX) and never had a boiling radiator.
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Old 20th March 2012, 15:42   #90
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Default Re: How often should we change gear oil?

^^^So were the cars of that time using only water (with no coolant added)?? And the pressure caps were less reliable? You mentioned missing also, so some cars ran without any pressure valve? Would it not lead to a burst??
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