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This might sound like a stupid question, but I am brand new to the FJ owners world. Can anyone tell me exactly what is the height of the breathers. I have found nothing but conflicting information. Thanks!!
 

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The lowest breather is the rear diff, maybe 20" off the ground on a factory stock vehicle.
 

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Thanks! That's about what I was thinking based off of what I could see by crawling under it, but I know that I had read that a stock FJ could drive through nearly 30" of water. Weather or not that is true is a different discussion all together.
 

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No FJ comes with an elevated rear breather. The factory breather works great, in 14 years guess how many time I have had moisture in my diff? Zero.
Relocating breathers was a cool and simple mod to do back when the FJ first came out which has managed to turn into a Gospel statement that it MUST be done if you do the offroad…..just like all early FJ's have bad diffs cracked fenders.
 

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No FJ comes with an elevated rear breather. The factory breather works great, in 14 years guess how many time I have had moisture in my diff? Zero.
Relocating breathers was a cool and simple mod to do back when the FJ first came out which has managed to turn into a Gospel statement that it MUST be done if you do the offroad…..just like all early FJ's have bad diffs cracked fenders.
Bingo. I never raised my rear diff breather either until recently. They're designed to keep water out.
 

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Bingo. I never raised my rear diff breather either until recently. They're designed to keep water out.
Actually, the "breather" on the rear diff (at least on a '14) is a spring-loaded check valve. It relieves internal pressure once the pressure exceeds some very low value, but does not allow anything to be sucked back into the rear axle housing, at least not when the poppet inside the breather is clean and new. Ditto for the front diff breather.
 

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Mine is a '10, and I had heard somewhere that the rear breathers we up by the fuel door.
No, the factory breathers for the rear differential and for the locking mechanism are located ON the rear axle housing. The common modification is to move them up near the fuel door.

Of course, to verify where YOUR breathers are located, you could take 30 seconds to crawl under your vehicle and actually look at them.
 

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I suppose this is another modification to make depending on how the vehicle is used. If subjected to prolonged or repeated stress, a relocation might be a good prophylactic against dangers of excessive pressure, heating & attendant stresses. Concur or dispute?
 

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Worth noting the breather relocate movement was not because of water coming in through the breather itself as it’s a one way valve. Supposition was that when suddenly cooled by water a hot diff (or trans) fluid would contract and, since its a one way valve, suck water in through the seals.

ARB relocate kit and such are a bidirectional breather for that reason. That said, as a San Diegan my ARB kit is uninstalled on a shelf in the garage. I tow 4K, see diff and trans fluid annually, never a hint of water with a handful of water crossings a year. Cold weather/cold water friends might be different.
 
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