Rear diff drain plug "hiss" sound on removal.sho

Long story short.

Drive rear axle seal is leaking.
Upon removing the fill plug to add fluid, there was a hissing sound from the fill bolt.
Is this normal? I'm not sure if it was air coming out or going in?
I did pull the diff breather off. I CAN blow air throw it.
I assuming it's good?


And yes, I was just over 1 quart low on rear diff fluid.
I pulled the drum off, spayed all pads, and stuck it back together.
Now I just have to get time to fix it.

 

Not normal.

 

OEM diff breather is a one way check valve, escaping air + heat and cooling created negative pressure. the hissing sound was air rushing in. normal.

 

I'm thinking this was it. As I had drove the truck 45 mins. before I open the plug. Hot fluid and cold outside air. Which should be a vacuum. Or air drawn in.

So.... I got the seals. Now how hard are they to put in?

And what's the chance that the leak is going to cause premature bearing failure?

Thanks for the input.

 

Once you get the drums off, it shouldn't be bad to replace the seals. As long as oil was splashing on them, the bearings should be fine.

 

Do the diff breather mod if you don't want it to happen again

 

The fact you havent done the breather mod may have contributed to the seals failing.

 

If the diff breather is failing then the heat produce during driving creates a positive pressure inside the axle housing causing the oil to be pushed through the seals.

 

OP says can blow thru the oem one way breather. that said yes adding a two way is the solution to potential pressure problems both positive and negative

 

Yes. This is correct. I plan to replace the seal tomorrow.
I hope that pulling the breather off and cleaning it will get me by until toyota can order me one.I'm not sure if mine got stuck closed? But currently it seems to be working.

On a side note. I have driven the truck since cleaning.
So far I haven't seen any more signs of fluid leaking.
But I'm still going to pull it a part and replace the seal.

Thanks for the help.

 

Sounds lIke it was indeed working as you were able to blow through it the flaw is the one way design , good luck with your seal replacement

 

I replaced the seal. Not very hard to do at all. pretty straight forward.
Hardest part was bleeding the brakes. You have take the line loose from the wheel cylinder.

Would it be wise to just go ahead and replace the breather valve?

 

Install a two way breather, instructional below :
https://www.tacomaworld.com/threads/differential-breather-mod-for-dummies-pics.15686/

 

Thank you sir. parts will be ordered monday.
So what do you think the chances of me blowing out the new seal until the parts get here?
I did pull the breather and it seems to be working.