Smell of diff oil in rear after driving and warming diff up.

Hey guys. I have a basically new 2021 O/R 6MT with 1700 miles on it. Best truck I ever had.

I changed the rear diff oil at 750 miles after doing a light driving/break in. Light amount of shavings consistent with other diffs I've observed. Drained and filled it up with Redline 75W85 until it weeped out, waited for the weeping to stop, and torqued the drain and fill to spec, a bit over a gallon which is the spec for this particular diff.

No visible leaks, the smell in the garage is gone in a few hours/next morning, and there are no greasy areas on or around the diff.

Can someone more knowledgeable than myself confirm that this is just the OEM breather passing stinky gas out when warm like after some serious rounds at an Indian buffet? Red line was more "fragrant" going in than what came out of the diff.

 

Maybe it's gear oil residue on the metal who stink when the diff became hot when driving. Sulfur in gear oil smell bad. Maybe there some on metal surface.

 

Thanks! You'd think that if there was a leak, the garage would smell like sulfur consistently. You're probably on the right track.

 

Use some degreaser around the diff and give it a good wash. Easy way to rule out residual fluid on the metal cooking off as everything warms up.

 

Maybe try given ‘er a wash. Odour from that stuff lingers for days. Doesn’t take much for it to smell.

 

Are You implying your rear differential is passing gas?

 

Pro tip: Don't get it in your hair -- your Beatles style hair...

 

Every day!

Took her for a 10 mile drive and no smell today. It's got to be all this random gas passin' or just the residue left from wiping with a towel. I'm going to relocate the breather for some trails, and when I do, I'll check the existing one to see if anything looks off and go from there. I appreciate you guys.

 

Have you tried popping in a couple beano tablets?.....lol

 

If I just did that in the first place, maybe I wouldn't need to wipe off any more residue!

 

Everything is going to get hot and stink. Drive it more.