i recently changed my rear end oil and came across something surprising.


i was under the impression that when a diff or trans started to wear out the oil it turned into a varnish rather than getting "dirty" like engine oil. when i have changed trans oil in the past that wasnt in good shape, it smelled like varnish and not that firmiliar sulfuric-you're-gonna-die-from-breathing-this-in smell.

when i pulled all the oil out it came out smelling like sulfur(maybe cause its 90 weight?) and it looked dirty like engine oil rather than that glossy looking varnishy fluid.

why is this? is the factory oil(thats what i removed) a non-synthetic oil? or is it because its 90 weight??? what would cause this difference?


as a side note the dif was just fine

 

Transmission and differential fluid are different, I don't see why you're comparing the look of dirty transmission fluid with the look of old differential oil?

Yes, it's normal for the oil to stink. The factory fill is, as far as I know, a straight 90 weight oil that is not a synthetic and meets GL5 specifications.

I would never expect used diff fluid to look anything like used transmission fluid...I don't get the point of your post?

 

Extreme pressure additives are needed in diff lubes. EP additives typically contain organic sulfur, phosphorus or chlorine compounds which chemically react with the metal surface under high pressure conditions.

 

Allthough IMO it has more to do with the GL-5 spec then it being diff oil

The LE-607 didn't smell that bad though, new or used.
How does the LE-1605 smell?
(like roses? )

 

most hondas that ive owned have a transaxel so a trans mated to the diff, like a FWD car...any of em...


those called out a motor oil and since they housed the diff i thought there was some resembelence.

but on all my RWD nissans i still had the varnishy smell vs the dirty oil smell like engine oil that i got out of teh s2000's rear diff.

is this common amongst LSD's?

 

And I bet you like the smell of napalm early in the morning also....!!!

 

I recently changed both my trans. and diff. fluids also and I did notice the strong smell, but it always smells like that. I refilled with Honda Manual Transsmission fluid and Mobil 1 diff. oil.