DIY: Rear Differential Breather Mod

Thank you! 6 years later it answered my question. I’m about to do my rear breather extension.

 

Thank you! I ordered 25 of them from Amazon and they fit perfectly.

 

Just ordered the oem housing and filter.

 

Those are nicer than my zip-ties... but I dont want all of the other zip-ties under the truck to feel inferior, so they shall remain

 

I mean, realistically... it's pretty overkill. I'm pretty sure even if the hose was free floating it would probably be fine for a very long time.



...however, you do get to look cool to a bunch of truck bros on your favorite forum though...

 

do you have a link to that clamp?

 

FIY gentlemen/ladies.. I wanted to find out what is the thread pitch of the OEM rear differential breather. It is M10-1.0 pitch. I wanted to find out because I wanted to get a brass coupler/nipple to run the breather tube up to the rear tail light or the gas cap.

My thought is to get a M10-1.0 8mm brass coupler and use a 5/16'' ID rubber/vinyl tube to run to the rear tail light or the gas cap. Probably need 6ft max in tube length.

My truck btw is 2007 Toyota Tundra SR5 4x4 5.7l Crewcab. I think all the other trucks would be similar, at least for this Generation.

Also to take the breather out you need a 14mm long socket.


OEM Toyota Breather thread pitch -


What the Brass Coupler looks like. You need a M10-1.0 8mm (5/16'' = 7.9mm)

 

I thought that fitting was an MPT (Male Pipe Thread)?

 

@Gaston It might be Male Pipe thread.. dont know.. does it matter if its Male pipe thread and a M10-1.0? I don't have any idea on pipe thread standards...

 

It would matter if that fitting is in fact a pipe thread, I didn't looked when I did mine but I can look at the old fitting when I get home a bit later. An M10x1.0 is a standard fine pitch straight thread while a pipe thread is tapered. A pipe thread is tapered and as you tighten it the threads seal the fitting. A straight thread doesn't seal itself and instead uses flat mating surfaces to create a seal. Again, I didn't pay attention to the fittings when I did mine as I just bought OEM Toyota fittings but I will look at my original fitting when I get home.

 

@Gaston I appreciate your explaining to me what is the difference between M10-1.0 and Male pipe thread.

Btw is Male pipe thread also = NPT or BSP?? just asking for a friend

 

No problem!

yes, MPT and FPT are the same as NPT. NPT is actually the standard by which these threads follow, MPT and FPT are just used to denote if they are male or female.

As for BSP, I don't recall off the top of my head but I'm pretty sure the angles of the threads are different between BSP and NPT, not meaning the tapered amount but the actual thread form itself. I don't think they are interchangeable either, I'd have to look through my handbook if you'd really like to know. I work more with straight threads than anything.

 

@baraynavab I looked at my original vent valve and the threads are tapered. I checked the threads with a 1.0 pitch gauge just for fun and it is close but it’s not quite the same, probably close enough you were able to thread it in. It checks really close to a 1/8” NPT thread so if I was buying a fitting that’s what I would get and double check it against the original.

 

So this is what I found from other Toyota forums in regards to the 1/8 NPT - 1/4 barb nipple.. and here's what I found out



Here's the info where I got this from.
https://www.fjcruiserforums.com/thr...ferential-e-locker-breather-mod.29229/page-45

 

So can I ask why not just go with the OEM part at that point? I can get it from my local dealer for $8.83 + tax.

 

LOL I need a few of them which is why.. need them for my Land cruiser as well.. its got 3..

BTW the Tundra 4x4 only has 1 or will it have one up front on the transfer case as well? if it does I'll need another one...so in all I may have to get 5..

also I am thinking of doing the 1/8 NPT to 5/16 barb.. dont think it makes any difference but its just a little bit bigger than 1/4 size hose.

 

4x4 tundra has two breathers under the hood for the front differential and either the transfer case or tranny, but they are allegedly up pretty high on the firewall already.

Don't imagine a larger barb would be an issue. Just need larger tubing I suppose.

 

Hey @Gaston and others - Question on breathers - Do the breathers allow air to go in and out? when hot and cold.. like really breathe like they way humans do? or is the breathing only done one way? to exhale out? so when the differential is hot the breather only allows the air to exhale out?

I am asking because if breathing is only one way there is a one way valve (see below) that can be put in to further ensure you are not getting any water from entering the differential system. These valves are pretty cheap as well and come in different sizes so you can put them in line.

 

gotcha
as already started, the front already has them relocated as seen by this post
https://www.tundras.com/threads/diy-rear-differential-breather-mod.5253/#post-75244

 

The factory breather seems to only be a 1 way valve. Out not in.

Some people replace the 1-way with those little crank case breather filters (at the end of their extension). I kinda figure Toyota made it a 1-way for a reason and just kept the factory piece on the termination behind my taillight.

 

My understanding is they are more of a check valve than an actual breather. They allow air to escape from the diff housing as it heats up and builds pressure.

 

Thanks for the write up!

 

Hey, sorry, totally missed this.

$9 M6-1.0 x 16mm Flanged Hex Head Bolts Flange Hexagon Screws, Stainless Steel 18-8 (304), Plain Finish, 25 PCS

M6-1.0 x 16mm Flanged Hex Head Bolts Flange Hexagon Screws, Stainless Steel 18-8 (304), Plain Finish, 25 PCS

 

I think Spyker wanted the link to the clamp. I do to actually. Ha!

 

OH! I just bought a 5/8" hose clamp from Lowes! They come in two packs. I used 3/8" oil hose, so ymmv if you used something of a different ID.



Here's a link to the one I got!

 

Thanks for that!

 

You're welcome!

Better late than never lmao

 

I picked up some at ACE. I put a rear diff kit on my Frontier. Zip ties will be gone shortly. Thanks PomDad!

 

Done. Great catch by @1794TX on the threaded tab above the diff!

 

Thanks all for the detailed instructions and part numbers.... I figure the sequoia version of this should be the same..
Any recommendations for easy routing on the sequoia?

This is added to the list of weekend things to work on...