Why does it stink?
Even better question, why does synthetic differential oil stink?

 

The smell comes from the high levels of Extreme Pressure antiwear additive. It's a giant glob of sulphur.

Nerdy stuff: http://en.m.wikipedia.org/wiki/Extre...ssure_additive

Not sure what your question about synthetic means. It's got the same additive.

Gear oils that don't meet GL-5 stink less btw.

 

Putting a wet dog in the back will cover all the standard smells produced by an XJ, or the driver.

 

Lol unless said wet dog rolls around in the gear oil all over the carpet!

 

Hell, sometimes the dog doesn't even have to be wet, LOL

 

She generally comes under for a look and a lick each time I service the underside. Usually her back is covered with a good slick from the trucks self applied floor preservative and automated oil excrement ports. I think she does it on purpose just to get a good rub down after.
As a note for skife, I've found my rear diff smells worse than my front and my fluid goes darker in colour than the front? Powertrax/Lockright in both D35 and D30(cable disco). Use the same Motomaster semi synthetic 75W90 and change every 50 - 65000 km (yearly). Both systems vented ok (extended vent lines) and no signs of water intrusion.
Always been this way. Both systems have been repeatedly serviced for bearings and seals over the last 350000km since I bought from the PO. No wear problems on the faces of the gear sets.

 

I know the feeling well, as I, too, also have a "shop supervisor" when I wrench, LOL

 

I've seen that photo of your "shop supervisor" lookin good in the shotgun seat and ready to roll!

 

That's her spot, LOL...and whenever someone rolls with us, she shows her disdain by standing on the center console, and slobbering all over myself and my passenger....she dislikes the back seat, and only rides back there if I have passengers, or the front doors are off. Once we hit the dirt, she's in the front seat, LOL

 

As someone that works on old stuff it gets ripe with age too.20 year+ gear oil will knock a buzzard a gut wagon.

 

All gear oil stinks to me!

 

This