gear oil at oil change

[Rawze]

(08-12-2019 )Jorg81 Wrote:  ...
So I'm ok to put it in even if im not demandated correct? Just want to make sure before I screw something up.

the basic answer is ...

No one can say if it is going to "screw something up" because it is totally dependent on how long you expect your emissions system components to last. Those components will wear out no matter if you add gear lube to your engine or not .. the real question is "how much shorter or longer will they likely last" ...

If a person were to get all "internet-rambo" about it then ...

Technically, the sulphides in gear oils may accelerate the wearing out of the emissions components. it is also "technically" hard on the environment. -- hence the same reasons that sulfur was stripped out of modern diesel fuels in the western countries too.

As sulphides in the gear oil gets into the exhaust, it creates molecules of sulfur-dioxide (the component in acid rain) and can be corrosive. This is technically not a good thing.

Next, is that there are differences between "active" and "inactive" sulphides that are in gear oils. Most modern gear oils claim to have mostly inactive sulphides. How this effects how much sulfur-dioxide production is unknown to me, I am not a chemist, so I will only use the worse case scenario assumption to be safe.

GL-5 oils are more prone to having higher sulphide content than GL-4 oils... this plays a role too, so GL-4 oils would certainly be better no matter how you look at it.

The only question is "by how much" of the conversion from whatever sulphides to sulfur-dioxides would actually occur.

it totally would also depend on how much oil the engine burned (amount of blo-by the engine has. Of that burned amount, Some percentage of that would likely be converted, albeit very low, as it needs oxygen for it to happen, and there is almost no oxygen in the exhaust of a diesel engine,.. but some will in fact occur.

1 gallon if gear lube at every oil change ...

* If the engine burned 1 gallon between oil changes then it would mean that whatever amount of sulphides in the gear lube per gallon divided by 11, would have gone through the exhaust system (very small amounts indeed). Even smaller amounts (unknown but a very small percentage of that) would actually be converted into something harmful due to lack of oxygen,.. bout it would not be none at all.

* If the engine burned 1/2 gallon between oil changes then it would mean that whatever amount of sulphides in the gear lube per gallon divided by 22, would have gone through the exhaust system. Again, some very small percentage of unknown quantity.


-- The results and the rate at which it can contribute harm in other words, is completely unknown, but it can be safely said to be very very little. Over time however, this can have an effect that can create problems.. the question is "how much time" that would take... <- it is anyone's guess, but I can say that there are many people who have used gear lube in their engines with those systems active and it did not cause any significant changes that were noticed as far as i know.

-- I.E. > No one can tell you, but it is very very little .. however over the long run (half million miles later say), a person may or may not see a shortened DPF or SCR component life?... who knows. - That is the question that cannot be answered... so if you have any doubts about it .. and you plan on doing everything absolutely possible towards making your emissions system last a million miles + then simply don't use it.

Though I am not encouraging it, or perhaps if you live in a foreign country where its legal ...

If your going to gut the system if it ever acts up (like 60% of all owner-ops do these days so that it does not put them in the poor-house) then it kind of starts to become an irrelevant discussion, as the effects that can be noticed are not likely to happen for several years especially if someone were to stick to only GL-4 oils, and by then, they are likely to have gutted the whole system out anyways.