Cleaning your differential vent
Thread Starter
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Cargo Master
Joined: Dec 2010
Posts: 2,123
Likes: 5
From: Fort Worth, TX
Cleaning your differential vent
Howdy all,
I unclogged my differential vent tonight and I want to share some information I was not able to find on my own. I have been noticing some significant leaking coming from not my rear main seal itself but the knuckle (universal joint) the drive shaft connects into right before the diff. Common symptoms are having gear oil slung on to your front fuel tank and/or gear oil leaking onto the ground.
I have been told and it makes sense that a blocked vent will force the fluid (under pressure) to escape from the weakest point available; be it a diff cover seal or in my case, near the rear main seal.
The following pictures will represent the diff vent and its dis-assembly. I had to use an Alan wrench to dislodge the the blockage. I could not blow it out with mouth pressure, thus further proving the theory behind the original leakage.
I unclogged my differential vent tonight and I want to share some information I was not able to find on my own. I have been noticing some significant leaking coming from not my rear main seal itself but the knuckle (universal joint) the drive shaft connects into right before the diff. Common symptoms are having gear oil slung on to your front fuel tank and/or gear oil leaking onto the ground.
I have been told and it makes sense that a blocked vent will force the fluid (under pressure) to escape from the weakest point available; be it a diff cover seal or in my case, near the rear main seal.
The following pictures will represent the diff vent and its dis-assembly. I had to use an Alan wrench to dislodge the the blockage. I could not blow it out with mouth pressure, thus further proving the theory behind the original leakage.
Thread Starter
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Cargo Master
Joined: Dec 2010
Posts: 2,123
Likes: 5
From: Fort Worth, TX
The assembly with the brake lines attached is self-contained and the vent simply passes through it. No need to disassemble the brake lines.
The vent tube itself mounts the brake line assembly to the axle housing. This is the part that was blocked with debris. Clean it out with the help of a small tool and spray it clean with brake cleaner. I applied some anti-seize to the threads upon reinstall.
My vent hose was long gone, so I had to fabricate a new one. I will post more pictures of that when the sun comes up. I used 5/16" hose and 3/8" copper flex tubing (Home Depot near the flare connectors - 1FT piece).
The vent tube itself mounts the brake line assembly to the axle housing. This is the part that was blocked with debris. Clean it out with the help of a small tool and spray it clean with brake cleaner. I applied some anti-seize to the threads upon reinstall.
My vent hose was long gone, so I had to fabricate a new one. I will post more pictures of that when the sun comes up. I used 5/16" hose and 3/8" copper flex tubing (Home Depot near the flare connectors - 1FT piece).
Thread Starter
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Cargo Master
Joined: Dec 2010
Posts: 2,123
Likes: 5
From: Fort Worth, TX
I went out for a dive not long ago this afternoon. I did not notice any leaking from the rear main seal area. Usually it drips and gets wet any time I drive the truck. I will check for drips later as well.
Coming next are pictures of my new vent.
Coming next are pictures of my new vent.
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Cargo Master
Joined: Dec 2010
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From: Fort Worth, TX
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Thread Starter
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Cargo Master
Joined: Dec 2010
Posts: 2,123
Likes: 5
From: Fort Worth, TX
It's been 3 days and not one single, solitary drip from that rear main seal. Thanks for the tip, you guys rock! One more step closer to getting this baby ready for the long haul. I just bought a set of replacement belts and I am waiting for some more time to install them. I got Gates belts except for the A/C belt (I went with the cheapo brand because I don't care about the A/C; it doesn't work anyway). $66 later I will feel better about not snapping a belt. I am thinking metal hose protectors in case of a snap and cut of a coolant hose. This is for another thread, though.
Senior User
Joined: Jun 2010
Posts: 235
Likes: 1
From: Balt. Co, MD
Thanks for this. I'm replacing my brake lines and came across a blocked breather last night, thanks to a mud wasp. Any clue where to get a new breather from? I'll try to clean mine out, but it's pretty rusty.
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Cargo Master
Joined: Dec 2010
Posts: 2,123
Likes: 5
From: Fort Worth, TX
I have not seen the breather fitting for sale in my dealings. Perhaps one from a junk yard would suffice. If you can get it out, it can probably go back in. Then, attach a hose to it so water does not get in there if you drive through a puddle, etc.
Logistics Pro
Joined: Sep 2007
Posts: 3,737
Likes: 179
From: Western Mass
Try this: Axle Breather Vent
Eaton, how long of a rubber hose did you use there? It doesn't look like much at all. I'd be worried that as the axle flexes it will rip out or bend either the vent or the tubing.
Thread Starter
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Cargo Master
Joined: Dec 2010
Posts: 2,123
Likes: 5
From: Fort Worth, TX
I don't see much that can be done without taking the axle out, etc. Probably not worth all the hassle. Make sure you change the differential oil in case water got in there.