Rear Diff Breather Function
07-11-2006, 12:27 PM
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Rear Diff Breather Function
So I went to the body shop today to do some maintence on my runner, for those of you that dont know why its at the shop look here. I changed the oil and front/rear/xcase gear lube. I have been wanting to get it done and since I leave saturday needed to do in at the body shop. Okay so, all was well, but when changing the rear diff fluid I noticed it was under a pretty good vacume. When I cracked the fill plug it sucked air in for a few seconds. So I pulled the breather to play with it and it wont allow air in, and it only allows air out with a very strong force...i.e. had to blow really hard to get it to open (gear lube tastes like A$$). Its not plugged with dirt, all that came out on the first blow... it just wont allow air back in. So is it normal for the rear diff to be under vacuum? I went to the parts dept at the stealership and they dont stock it, so I couldnt compare them...but I orderd one and it will be in tomorrw, just wanted some opinions first.
07-11-2006, 12:39 PM
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http://www.wattora.com/mods/diffbreather/ read his edit on 12/12/03. I tested this myself also when I extended my breather using the stock breather and found the same results as you and WATTORA. He also has a pic on there of the thing taken apart. Its easy to see that air can escape but cannot come back in. I don't think you did anything wrong as this is how it came from the factory. Why? I don't know. I know he eventually took that off and replaced it with a free flowing fuel filter so air can go in and out. Good luck!
Last edited by drguitarum2005; 07-11-2006 at 12:44 PM.
07-11-2006, 01:23 PM
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Originally Posted by Spectre
(sorry for the hijack)Damn dude..thought you were going to the Stan.
Waiting till it gets nice and COLD huh
Waiting till it gets nice and COLD huh
I am, just took longer than anticipated for my orders... I leave saturday for the trip... and I wouldnt mind the colder weather...
07-11-2006, 01:27 PM
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The breather is designed to "burp" air out so that it is open to contamination for as little time as possible. It takes a bit of steam to get it to burp, especially from puny human lungs, but a hot diff can do it.
The breather is also designed the minimize stuff getting back in, water, air, urine, whatever, but, it is NOT water tight. When there is a vacuum on the inside, it very slowly let's air back in. Of course, if you happen to submerge it when there is a vacuum, that is just as likely to be water going back in.
The breather is also designed the minimize stuff getting back in, water, air, urine, whatever, but, it is NOT water tight. When there is a vacuum on the inside, it very slowly let's air back in. Of course, if you happen to submerge it when there is a vacuum, that is just as likely to be water going back in.
07-11-2006, 01:28 PM
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Originally Posted by drguitarum2005
http://www.wattora.com/mods/diffbreather/ read his edit on 12/12/03. I tested this myself also when I extended my breather using the stock breather and found the same results as you and WATTORA. He also has a pic on there of the thing taken apart. Its easy to see that air can escape but cannot come back in. I don't think you did anything wrong as this is how it came from the factory. Why? I don't know. I know he eventually took that off and replaced it with a free flowing fuel filter so air can go in and out. Good luck!
Well at least its normal. I just never noticed it before... I am guessing the seals on my runners axle are good since it hasnt been driven in 2 weeks and still had the vacuum... Its not my wheeling rig, so I dont think i'll worry about it.
07-11-2006, 01:39 PM
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Originally Posted by WATRD
The breather is designed to "burp" air out so that it is open to contamination for as little time as possible. It takes a bit of steam to get it to burp, especially from puny human lungs, but a hot diff can do it.
The breather is also designed the minimize stuff getting back in, water, air, urine, whatever, but, it is NOT water tight. When there is a vacuum on the inside, it very slowly let's air back in. Of course, if you happen to submerge it when there is a vacuum, that is just as likely to be water going back in.
The breather is also designed the minimize stuff getting back in, water, air, urine, whatever, but, it is NOT water tight. When there is a vacuum on the inside, it very slowly let's air back in. Of course, if you happen to submerge it when there is a vacuum, that is just as likely to be water going back in.
Good deal, thanks Rob.... I would guess the vacuum was just below the "sucks" threashold, which is why it has held for 2 weeks....
Nice to know I dont have to go do more repairs in the parking lot of the toyota body shop...
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