Did the diff breather mod - noticed something strange

TW,

I finally got around to completing the diff breather mod yesterday on my 2015 DCSB OR. It went well. I decided to reposition the breather behind the driver's side tail light. High and dry!

One question, I noticed when I unscrewed the original diff breather, I had a shit-ton of air leak out of the hole. The diff wasn't particularly hot. The truck had been sitting in my driveway for two hours before this work.

Just curious if this is normal, or did I discover that my breather wasn't working properly? If so, could this cause other issues I should investigate? I am due for my 30k maintenance soon, so I plan to change the diff oil regardless.

Any insight would be appreciated.

Thanks

 

I think it was stuck shut. Should allow for pressure equalization as oil temp raises and lowers obviously, can blow seals if pressure gets high enough.

 

Mine did the same thing when I removed the stock one, or short one I should say.

Truck had been sitting under the car port all night, not driven for over 15 hours or so.

 

Hmm. So it sounds like a common problem, but it's also technically a bad thing.

That sucks. I wonder if I should double-check my front diff breather?

 

i know, i know, old thread. but i'm reviving it just in case op didn't figure this out, or someone else finds this thread...

the stock breather on the rear diff is not really a breather. its a one way pressure relief. it lets air out but not back in. this means that over time and use, you can develop a significant vacuum in your diff, leading to water getting in through axle seals (this is the true reason for relocating)

@glock24 what this means is that what you really heard was air getting sucked IN the diff and not out...

the fronts are actual 2 way breathers. you should not have this issue unless they have been clogged somehow

a little info on part numbers: Mixed rear diff breather mod parts question...
how to: Differential Breather Mod for Dummies (Pics)

i would recommend installing behind driver side tail light, like op did.