lewdog998
New member
got me wondering to.....I have done the rear diff, and e locker. Are there others that need to be done?
Rear Differential Breather Mod For Dummies
- Thread starter Cymon
- Start date
got me wondering to.....I have done the rear diff, and e locker. Are there others that need to be done?
jawkdna
New member
Seems that the Rear Diff and Locker are the only two that need to be done... the others are already vented up to the engine bay, or at least that is what I have read and seen...
Saker
Senior Member
That’s correct, only 2 are the rear diff and locker.
Others are behind engine above tranny.
Frasher4Runner
Member
4Runner noob - what's the purpose of this?
lewdog998
New member
From my understanding.....the breather valve lets the differential breath and not build up pressure when it gets up to temp. If it did not have this valve,, it would push pressure out the axle seals and cause a leak.
The diff will normally equalize with outside pressure. But if the diff is submerged and rapidly cools, you can create a negative pressure situation. If the valve is below water, it will not let water in, but it will suck in water past the axle seals. relocating the valve allows it to do its job.
or
it keep water from gettin in your rear end....nobody like a watery rear end.
Frasher4Runner
Member
Humble Leader
Senior Member
this is a great write up. OP did you jack the truck up at all before doing this or just crawl underneath?
I wonder though how necessary this mod really is. the TRD PRO models at least to my knowledge have the same diff breather valve as all other trim models. surely the toyota engineers would have suspected folks who buy the TRD pros are likely to go through water. it's not costly to do and could easily be done factory. I have read that the toyota valve is one of the better ones though (opinions vs. actual research)
I'm curious to know just how much of a temperature difference is needed between the rear diff and water to actually cause water to be sucked in through the axle seals. if you get to a deep water crossing and exercise proper wheeling protocol, you will walk the crossing. that would likely cool your diff off before going through. unless you are going through sustained diff submerged cold waters I don't see an issue. look at boat launches, never heard of anyone having a diff problem launching a boat - mind you the weather is always warm and the diff is likely cooled off by the time you access the ramp. I've seen some rigs go pretty deep in
I understand the purpose of this mod, I'm just questioning the necessity of it. the diff breather is probably not much lower than your door sill, it might actually be higher (I'm just guessing here, on a stock vehicle). how many of you cross water that high?
I wonder though how necessary this mod really is. the TRD PRO models at least to my knowledge have the same diff breather valve as all other trim models. surely the toyota engineers would have suspected folks who buy the TRD pros are likely to go through water. it's not costly to do and could easily be done factory. I have read that the toyota valve is one of the better ones though (opinions vs. actual research)
I'm curious to know just how much of a temperature difference is needed between the rear diff and water to actually cause water to be sucked in through the axle seals. if you get to a deep water crossing and exercise proper wheeling protocol, you will walk the crossing. that would likely cool your diff off before going through. unless you are going through sustained diff submerged cold waters I don't see an issue. look at boat launches, never heard of anyone having a diff problem launching a boat - mind you the weather is always warm and the diff is likely cooled off by the time you access the ramp. I've seen some rigs go pretty deep in
I understand the purpose of this mod, I'm just questioning the necessity of it. the diff breather is probably not much lower than your door sill, it might actually be higher (I'm just guessing here, on a stock vehicle). how many of you cross water that high?
docsnavely
New member
If you're submerging your entire back axle when launching or recovering a boat, you're either doing something wrong or you don't have the right equipment for the job.
As for the necessity of breather relocation, that's left to the owner. I don't do lots of water crossings, but at the same time I would like to be prepared for any situation. There have been a number of times where I crossed a stream only to come back through the following day and it has risen by about a foot. What if that ends up being higher due to unexpected weather and I now have to ford a small river in order to get home? I would rather be prepared than potentially let water into my diff.
If you live in the southwest though, it may not be as much of a concern.
Humble Leader
Senior Member
I've seen some pretty deep boat launches but never have I done so myself. Always better to have something and not need it vs. the other way around, I get it. I've been thinking about a breather for quite some time. looked at the arb kit, that plastic hose though I don't think will stand up over time to repeated cold winter temps. anyone on here have this kit and regularly get -20F or colder temps during winter with warm summers? any issues?
mbumpus11
Member
I definitely don't get to -20F in Texas, but we get blazing hot in the summers. The ARB Kit hose is fine for a little bit, but mine made contact with my exhaust manifold and it absolutely melted immediately (which makes sense).
I replaced it with some thicker clear hosing I found at the hardware store, and it had some pretty aggressive temperature capabilities from what I recall. I have driven and spent plenty of time in Kansas when at/just below 0F, but never as deep cold as you're talking. Still...would definitely be a proponent of swapping the standard ARB kit hose with new hose. I believe I have pics from my hose swap in my threads somewhere. Will look.
EDIT*** for @HumbleLeader - Link to my swap/re-install where you can see the type of hosing I bought: https://www.toyota-4runner.org/3314251-post227.html
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Humble Leader
Senior Member
thank you I will check out the link. appreciate the help
