Rear Diff Breather Not Working Right?

[RPC]

So I pulled the rear diff breather today getting ready to do the Extended Breather mod, and as I was unthreading the breather I got a pretty big release of air at the last few threads. I hadn't driven at all and the vehicle was garaged (= totally cool).

I have read stories of folks' extended breather tubes getting kinked or clogged and blowing a seal. Here's one: Rear Diff breather mod, improved - Page 3 - TTORA Forum Should I be worried about a faulty valve on mine? Only 15K miles and no offroad or H2O driving at all yet.

I would hate to have a faulty valve, blow the rear seal after doing the extended breather mod, and have Toyota charge me for the damage claiming the mod caused it...

Ideas? Thanks!

 

[martini]

The hissing/air release is normal: http://www.toyota-4runner.org/off-roading-home-monst4rs/123-breather-install.html

 

[RPC]

Yeah, that's one of the threads I referenced.

But isn't the breather supposed to allow the diff to equalize air pressure? Why would there be any pressure in the differential to release?

 

[Jed]

Yeah, that's one of the threads I referenced.

But isn't the breather supposed to allow the diff to equalize air pressure? Why would there be any pressure in the differential to release?

It's supposed to release pressure inside the differential housing. Are you sure it was pressure and not vacuum? You can develop a small amount of vacuum (from the heating & cooling of the internals) inside the housing, but the valve is obviously just one way, so you would probably hear outside air being sucked in if you removed the valve while there was negative pressure in the housing.

 

[RPC]

You know what Jed, I'm not sure it wasn't vacuum. I considered that as I started this thread but figured air pressure was more likely. I bet you're right.

 

[CJ3Flyr]

You know what Jed, I'm not sure it wasn't vacuum. I considered that as I started this thread but figured air pressure was more likely. I bet you're right.

I would agree with Jed's guess, I'll bet it suction.

 

[mndanielsncsu]

I was actually planning on doing the extended diff breather mod tomorrow as I just picked up the parts today. I'll let you know if I experience the same thing and if it's vacuum or pressure.