Gear oil smell

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What is it that is in gear oils that make them smell, I can always tell the gear oil because of the horrible smell. I thought it was something in old oils but today I changed my oil to have that horrible smell from a fully synthetic oil.
 

djb

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Sulfur-based extreme pressure (EP) additives are the source of the smell. The smell intensifies when they are activated. Some mistake the smell for the oil having "gone bad", but a strong smell just means that there was a robust additive package.
 

MolaKule

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What is it that is in gear oils that make them smell, I can always tell the gear oil because of the horrible smell. I thought it was something in old oils but today I changed my oil to have that horrible smell from a fully synthetic oil.
The odor comes from the sulfurized olefin and the phosphorus esters, regardless of the base oil used.
 

galaxy333

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Originally Posted By: Miller88
I had a jug break open on the carpet of the Jeep. Horrible smell on a 90 degree day.
I know how you feel I spilt some in the back of my car.
 

MolaKule

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Originally Posted By: galaxy333
What is it that attacks the sycro rings? Is this in a fully synthetic like this? http://www.opieoils.co.uk/p-981-fuchs-ti...sion-fluid.aspx
Most dedicated Manual Transmission Fluids contain mostly ZDDP as the anti-wear additive with a special friction modifier for improved synchro engagement. MT's do not need Extreme Pressure (EP) additives. The Extreme Pressure Additive (EP) of sulurized olefins and phosphorus esters is mostly used in differential gear lubes with hypoid type pinion gearing since the differential sees higher loads than do manual transmissions for cars and light trucks. Now both types of lubes contain "yellow metal" sulfur buffering additives generally called anti-corrosion agents that keep any sulfur chemistries from attacking any copper alloy (brass or bronze) components. White Paper: Technology of Manual Transmissions and Lubes
 
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I was going thur my old too little, they shrunk!!!, clothes and found a Cragar t-shirt that smelled like heaven....90wt gear goo.
 
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Except Subaru and some Porsche where they thought it was a genius idea to combine the Front diff and the MT.
Originally Posted By: MolaKule
Originally Posted By: galaxy333
What is it that attacks the sycro rings? Is this in a fully synthetic like this? http://www.opieoils.co.uk/p-981-fuchs-ti...sion-fluid.aspx
Most dedicated Manual Transmission Fluids contain mostly ZDDP as the anti-wear additive with a special friction modifier for improved synchro engagement. MT's do not need Extreme Pressure (EP) additives. The Extreme Pressure Additive (EP) of sulurized olefins and phosphorus esters is mostly used in differential gear lubes with hypoid type pinion gearing since the differential sees higher loads than do manual transmissions for cars and light trucks. Now both types of lubes contain "yellow metal" sulfur buffering additives generally called anti-corrosion agents that keep any sulfur chemistries from attacking any copper alloy (brass or bronze) components. White Paper: Technology of Manual Transmissions and Lubes
 
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Originally Posted By: stchman
Gear oil does smell badly, but LSD additive might smell even worse.
Yes, especially the Motorcraft XL-3 stuff, which makes plain old gear oil (even very heavily additized ones) smell like expensive perfume, and permeates the air (and through many multiple layers of ANYTHING one puts the sealed bottle into) at least 1000x more than skunk juice!! LOL eek
 

galaxy333

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Originally Posted By: MolaKule
Originally Posted By: galaxy333
What is it that attacks the sycro rings? Is this in a fully synthetic like this? http://www.opieoils.co.uk/p-981-fuchs-ti...sion-fluid.aspx
Most dedicated Manual Transmission Fluids contain mostly ZDDP as the anti-wear additive with a special friction modifier for improved synchro engagement. MT's do not need Extreme Pressure (EP) additives. The Extreme Pressure Additive (EP) of sulurized olefins and phosphorus esters is mostly used in differential gear lubes with hypoid type pinion gearing since the differential sees higher loads than do manual transmissions for cars and light trucks. Now both types of lubes contain "yellow metal" sulfur buffering additives generally called anti-corrosion agents that keep any sulfur chemistries from attacking any copper alloy (brass or bronze) components. White Paper: Technology of Manual Transmissions and Lubes
What a fantastic reply and great read on the white paper thank you for that. I now have another question, around 10,000 miles ago I changed my gearbox oil for this: http://www.opieoils.co.uk/p-69412-castrol-syntrans-fe-75w-full-synthetic-gear-oil-gl4.aspx My car is a Ford Galaxy with the MT6 gearbox and that oil was supposed to be made for it, when I drained the old I assume factory oil out it was bright clear and appeared to have no bits in it, my words to my wife was I think I've just wasted time and money changing this out, after 4,000 miles the dual mass flywheel needed replacement so it went in under warranty, I later found out the dealer had been charging for parts not fitted to the vehicle so I became worried as to what they might have put in the gearbox. It felt fine shifting etc but I felt I needed to change it, then I found out Ford had come out with a later spec oil to use so I chose the Fuchs TITAN SINTOFLUID SAE 75W-80 which matched the new spec. When I drained out the oil yesterday it came out much darker than the first time I had changed it and it had particles of brass in it very small but if you rocked the tray I drained it into you could see it glinting in the oil, it was in suspension it didn't seem to drop to the bottom of the oil even in an hour. What has me thinking is did they change the oil for something different which is darker but if they had it would have only been in for 4,000 miles or did the Castrol I put in go dark and get particles in it? What do you think? The strange thing is I am a sedate driver I have never rushed a gearchange and have never heard a grind of any type so where has the particles come from in such a small time when from the original factory fill which was in for over 40,000 miles was still clear and had not visable particles in it?
 

MolaKule

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Your timeline verses fluid is not clear. Which oil did you drain out last, the Syntrans FE or the Titan Fuchs?
 

galaxy333

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Originally Posted By: MolaKule
Your timeline verses fluid is not clear. Which oil did you drain out last, the Syntrans FE or the Titan Fuchs?
Hi sorry about that, I bought the car with approx 40,000 miles on her I changed the oil to the castrol Fe75 the oil that came out I would imagine was original it was clear with no apparent particles, I refilled using the Castrol FE75 which is also clear looking. Approx 14,000 miles later the DMF failed so went into the dealers under warranty they would have to have taken out the gearbox oil, I was concerned because after I got the car back I found they had charged Ford for work not done and also charged me for parts not fitted. This concerned me enough to want to check the gearbox oil. So I drained it and found it to be a dirty colour with particles in it. So I have done maximum 6,000 miles on whatever they put into the gearbox, unless they drained it and saved the oil and put it back? So it either has the old Castrol oil I put in or something they put in it, the gearchange felt fine but I didn't trust them. How could the gearbox do it's first 40,000 miles on oil that came out clear with no particles change to oil that has been in maximum of 20,000 miles (if they put back in the Castrol I put in at 40,000 miles) or 6,000 miles if they put a new oil into it? This oil I have now put in is the Fuchs 75W 80, the gearchange is slightly stiffer when cold than before but feels nicer when it's hot as it did feel slack when hot. What could cause the brass coloured particles in so few miles when it had none after 40,000 miles? As I said I drive sedately and I have never worn a clutch out let alone a gearbox in 35 years of driving and have had cars that I've done 295,000 miles in?
 
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MolaKule

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I think you did right by changing the oil after you got it back from the dealer, since you never know what they put in there. I would drain a small amount into a white bucket at 5,000 miles and see if more or less particles appear. It is not unusual to see some "sparkly" since the there is always a small amount of steel and brass being worn away.
 
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