# Rear Differential Vent Modification



## jkon (Mar 30, 2006)

I have been reading on-line about a rear differential vent modification that a bunch of the Frontier owners are doing. They are removing the original rear axle breather then replacing it with Nissan part number 38323-C601A which is nothing more than a barbed hose fitting, then running 6 ft. of fuel line from it and routing it up into the rear tail light housing and terminating it with just a simple in-line fuel filter to protect opening from dust and dirt. My factory rear axle breather failed but I was fortunate that it only blew out my rear diff cover seal. Says this mod provides better axle venting by not only letting air pressure escape but also allowing air back in. They also say that is sort the manner in which the front differential is vented. I would like to perform this mod but my only concern is possible condensation build-up resulting in water getting back into the real axle and differential over time...especially in Massachusetts Hot/cold climate. Should this be a concern? Thanks.


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## BRubble (Jun 22, 2014)

> My factory rear axle breather failed but I was fortunate that it only blew out my rear diff cover seal.


What do you mean,, when you say it failed?

It's just a simple threaded short metal Hollow Pipe, with a crimped metal cap over the top, that allow's for Fluid Expansion. The Breather need's to be checked from time to time. The Frontier is not designed to go through Deep water or mud, that might stop the Breather up, or containminate the Axle Oil.

I do have an issue with Nissan not includeing, checking and cleaning the Axle Vent.

I had a '93 hardbody for 20 year's,, and never had an issue with the axle vent stopping up,, but I did check the vent from time to time or at least, when I changed the Axle Oil. When I check the axle vent,, I take it out,, and clean it with diesel fuel,, then blow it out with the air compressor.

In the Cold Country where haveing to drive the Truck in Snow, etc,, I can see that the Vent might get clogged up,, and would need to be checked more often. Or driveing on Dirt/Gravel Road's,, I can also see that the vent could get clogged up by Dust and Dirt, and need to be checked more aften.

I haven't needed to do the Axle Vent Mod,, so I can't advise there, but the Mod, will need to be checked from time to time as well, to make sure the vent is free flowing.

Good Luck


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## Walt Gibson (Oct 23, 2018)

*thread size for the Rear Axel Differential Breather Vent?*

Does anyone know the thread size for the Rear Axel Differential Breather Vent? are they the same size for a 2011 Xterra and a 2015 Frontier? I would like to replace the original with a brass fitting and hose and an air filter up high so that the Salt Water wont rust it out when launching my boat and the nasty salt stuff they use on the roads in winter in New England rusts everything. You can Email me


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## jkon (Mar 30, 2006)

It is a 10mm x 1.0 barbed fitting. I got mine on Amazon. Do not use any other thread such as BSPT because it is not the correct thread. Amazon.com: Fitting M10 M10X1.0 to 9mm OD or 5/16" Hose ID Barb (2 Units): Automotive


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