: Rear Diff Breather


CoTacoTRD
09-23-2007, 05:52 PM
I am curious I looked at Jackets website with all of his mods and such and noticed the extension of the rear diff breather. My question is did Toyota create a design flaw by not extending the breather somewhere further up than this or is this breather designed as a one way valve and would not allow water to go into the diff but allows it to let off pressure as needed. To me if Toyota is building an Off Road truck some thought would be put into this. Water fording is a common thing to do on off road trails even on easy trails. So I would think that Toyota would think about this and not allow such a simple failure point for the rear axle to exist. Or am I just kidding myself or is this breather only one way? My breather is still stock and is directly attached to the diff with no extension at all. Should this be something I should do ASAP?

darwink1
09-23-2007, 06:16 PM
yes i blew my pinion seal and ultimately my diff because it was not extended.

spindleshanks
09-23-2007, 06:26 PM
The front diff breather comes extended from the factory. On my Tacoma it's on the driver side fender well under the hood. The idea is that the diff warms up as it's used, and vents out air as the fluid expands. A sudden submersion in water would have a cooling effect on the diff, thus causing the fluid to contract and draw in air and/or water with it. The breather is, in fact, a two-way valve.
Are you gonna ruin your differential every time you drive through water with a stock breather? Absolutely not. I'd say it's freakishly rare. ***EDIT: I guess it may be more common than I thought, Darwink...*** But for a $10 mod that a caveman could do, it's nice reassurance.
It's also a fun opportunity to test your creative mechanical skills. There is a plethora of options of how to make a diff breather mod. I ran mine into the fuel fill area behind the fuel door. http://im1.shutterfly.com/procserv/47b6dc31b3127cce9735c431f8cd00000016102BZt3DNszY4

RedRunnertc
09-23-2007, 06:45 PM
This should be the FIRST mod anyone who takes their truck offroad should do.

It's more than "peace of mind" - true, you may not suck in water every time, but eventually you will, and if you don't promptly change the fluid (and face it, checking after every run gets to be a PITA) you will destroy your diff.

00regcab
09-23-2007, 07:53 PM
that settles it...

diff breather mod this week!

Im assuming there is a write up around here somewhere eh?

CoTacoTRD
09-23-2007, 08:08 PM
Yeah I was wondering about a write up as well. I see that it is easy mod but what do you need to get it done? I am mechanically inclined but I like to know what I need before I get started. Anyone have any suggestions? Peace of mind from this is well worth the time and cost.

CoTacoTRD
09-23-2007, 08:11 PM
Found it!

http://www.wattora.com/index.php?page_id=12

Jacket
09-23-2007, 09:51 PM
Here's what I used:

90404-51319 - Union (Toyota part)
90930-03136 - breather vent (Toyota part)
two stainless steel hose clamps
5' or so of 3/8 fuel line
zip ties to secure the line

I put mine in the same place that spindle did, although you could also put it in the bed somewhere (cubby?). Looks like you found a step by step write up, but it's a pretty simple process of unscrewing the existing breather, and replacing it with the union, running hose from the union to where you will seat the breather, and then attaching the breather to the other end. Clamp both hose attachments, secure the line, and your good.

Good luck!

devinsixtyseven
09-24-2007, 04:37 PM
The ball valve is supposed to be one-way...but it's not. It's supposed to close off when the diff cools and sucks in air suddenly, like a water crossing...but they get clogged, dirty, jammed, rusted, torn off, whatever, and then you get water in the diff.

If you think you're running water, pull the drain plug a little bit. If good oil seeps out, you're fine. If you're getting that thin gunky stuff, or straight water, flush it.

Also FYI if you did get a bunch of water in there, the best way to get everything out is free the rear axle (disco rear dshaft, pull ubolts is all you need to do), pull the fill plug and point the pinion up...do it after you've drained it normally, so you can clean any metal off the drain plug, then tilt it up and let it sit for a while.

-Sean

spindleshanks
09-24-2007, 08:03 PM
The WATTORA write-up is a good one. I used it. I remember reading somewhere that gear oil from the diff will get into the line and pool up in any bends in the line, blocking airflow, but I checked my line the other day and it was fine.

Quick Draw
09-25-2007, 06:13 PM
Hmm....I can't believe I haven't heard anything about this until now... Well, I will do it on my new axle when I get it...should be anyday now....

00regcab
09-25-2007, 09:19 PM
just did this tonight...

bit of info for you pre-taco guys reading this (very few lol)

the filler neck area is STEEL, not plastic like on the tacomas... so i had to route mine into a hole on one of the bedside support beams.

numb_fingers
09-26-2007, 04:43 PM
Found both parts online but there is a minimum purchase of 17$ so does anyone want me to pick them up a part or two? I live up in Thornton

00regcab
09-26-2007, 06:26 PM
Found both parts online but there is a minimum purchase of 17$ so does anyone want me to pick them up a part or two? I live up in Thornton

go to your local ace hardware...

1/8NPT male brass fitting, with a 1/4" barb on it... worked perfect for me... and it only cost me $1.29 + tax

numb_fingers
09-26-2007, 06:27 PM
Damn... 20 min too late

00regcab
09-26-2007, 08:44 PM
heres a pic of mine... sorry it was getting dark:

http://users.4x4wh.com/4x4master/yota/diff.jpg

Lysmachia
09-26-2007, 10:10 PM
Mmmm Diff Breather pr0n!!! God I love CoTTORA (And props to WaTTORA and Rob's crew for the write up!)

00regcab
09-26-2007, 10:35 PM
lol anybody else notice my car tire sidewall exhaust hangers?

I dont know wtf is up with them being there :shrugs:

oh well, they'll get replaced when i get the new exhaust done.

sl3807
08-18-2008, 10:11 AM
go to your local ace hardware...

1/8NPT male brass fitting, with a 1/4" barb on it... worked perfect for me... and it only cost me $1.29 + tax

FYI

So I went to do this mod on Saturday so I could make it up to MSV. I picked up the 1/8 NPT brass fitting. I pulled the stock breather and compared the threads. They were different :( . Althought they appear to be very close, the brass fitting is a 1/8-27 NPT tapered pipe thread, the breather is a M10x1.0 thread. They looked close enoough that I thought i would give it a try. I couldn't even get the brass fitting to thread in one full turn. Apparently the new gen Tacomas's have a different thread, or were manufactured to a tighter tolerance so the 1/8 NPT won't quite fit. Called Toyota this morning and they will have the union here tomorrow morning.

Jacket
08-18-2008, 10:17 AM
FYI

So I went to do this mod on Saturday so I could make it up to MSV. I picked up the 1/8 NPT brass fitting. I pulled the stock breather and compared the threads. They were different :( . Althought they appear to be very close, the brass fitting is a 1/8-27 NPT tapered pipe thread, the breather is a M10x1.0 thread. They looked close enoough that I thought i would give it a try. I couldn't even get the brass fitting to thread in one full turn. Apparently the new gen Tacomas's have a different thread, or were manufactured to a tighter tolerance so the 1/8 NPT won't quite fit. Called Toyota this morning and they will have the union here tomorrow morning.

Yea - were talking about a few dollars difference here. No reason not to go OEM.

PS - Our diffs were submerged yesterday....

RedRunnertc
08-18-2008, 11:17 AM
I have a 1/8" NPT tap for anyone doing this mod with regular hardware...

ike
08-18-2008, 12:27 PM
I would just buy the toyota part.

00regcab
08-18-2008, 12:34 PM
my 1/8 NPT thread fitting fit fine in both my pre-taco, and my taco, it threaded damn near all of the way in by hand.

Don_G
08-18-2008, 08:22 PM
I've seen a lot of variation on whether the 1/8 NPT fits or not. I just used the Toyota part. You can find them on most junk intakes, by the way...