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Discussion Starter #1
I decided to do this mod since my rear differential breather vent was rusted.

The rear differential breather valve or breather cap sits on top of the rear differential. It is pressed in and spring loaded. Hot air from the rear differential vent through this breather valve. You can check the condition of the breather valve by first jacking up your car or using ramps. I found the driver side was easier to reach over the top of the rear differential to check near the rear differential drain plug. There is very little room on the top but just enough room for your hands to feel the valve. I can feel the valve was rough and not movable. I can't see it but I am sure it was rusted. There was no road crud that I can feel. The problem with a rusted breather valve is that it could crumble if it is loosen. Another problem is that a stuck breather valve will eventually blow the seals and cause a leak in the rear differential. I decided to create a new breather valve from the fill plug.

Here is a picture of the rear differential breather valve:
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Here is the parts I am going to use for my new breather mod:
  • 9 feet of rubber hose (3/8 inch) rated for oil/fuel. If you want something stronger you can use transmission hose for higher heat.
  • 2 hose clamps. I used 5/8 stainless steel hose clamps from here.
  • 1 hose barb fitting adapter. Size M18 x 1.5 to 3/8 (9.5mm) from here. Amazon sell them if you want to pay a bit more and get it quicker.
  • 1 vent valve. I got a Dorman 924-284 bought here, but there are many alternative valves you can use.
  • Hardware to mount valve. I did not buy my mounting kit. I used what spare parts I had around.
  • Cable ties
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So lets get started and go to the back and look at the access panel on the driver side and open it up.
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Remove the panel and the rubber plug and push the hose through the hole and guide it over the spring coil towards the rear differential fill plug. You should have enough length so that you can fit it over the barb adapter without too much of a bend in the hose.
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Look for the fill plug which is on the passenger side.
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Once you have your hose over towards the fill plug remove the fill plug and connect the barb fitting. Finally connect the hose clamp.
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While you are under the car check a few places the hose can be secured down with cable ties. Sorry forgot to add that to the part list picture. I think I used 2 or 3 cable ties near the spring coil. There is a cable near which I tied it down to.

Now back to the rear of the access panel mount your breather vent. I chose to mount the breather vent inside of the car but it is up to you if you want it outside if you may think it smells.

Here is my mounting kit from spare parts I found at home.
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Here it is mounted to a hole already in the car:
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Here is the final breather valve in the back:
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Hey Mods, what do you think about making this a sticky? Great job DL175!
 

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Discussion Starter #3
There appears to be a rubber tube in the rear differential which draws in fresh air. This is not to be confused with the breather valve on the top that exhaust hot air. More information can be found in this thread. This tube does not seem to eliminate a problem if the top breather valve stop operating which wll eventually blow the seals causing a leak.
 
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