Diff Breather Question

[Baba Booey]

I plan on doing the popular rear diff breather mod. I understand that there are two breather caps in the engine bay, which are for the front diff and transfer case. Is this correct?

The reason I ask is because I was looking at some breather kits on the Internet (I plan on using the homemade version), and they mention the need to do the mod on both the front and rear diffs.

For example, check out this site, about half-way down the page:

Northwest Offroad Specialties

In any case, I am just looking for some reassurance that the front diff has been taken care of at the factory. Could the two that are in the engine compartment be for the tranny and the transfer case, and not for the front diff?

 

[Good Times]

front and center are extended already. no need to worry about those.

just extend the rear. Easy to do.

Good luck

 

[Baba Booey]

GT,

Thanks. These websites that imply that both the front and rear must be done should get their act together.

I'd be pretty po'd if I went through the trouble and expense of getting to the front diff only to find out that it was already completed at the factory.

I don't do much serious wheeling, but I do have a small boat that I fish with. I was concerned because the rear diff may take an occassional dunking when putting the boat in the water.

 

[greasefingers]

look here

http://www.toyota-4runner.org/showthread.php?s=&threadid=123&highlight=diff+breather

 

[SKO450ES]

Well I broke down and did it last night for my 96 Runner. What I noticed is that the original breather when I tried to force air thrue it none would go through. But the new one did have air go through when I blew through it. Did anyone notice this?

 

[Thai]

I would check your engine bay to confirm two breather tubes. They should look similar to these on the FJC:

http://www.toyota-4runner.org/attachment.php?s=&postid=171099

V6 4runner 4wd has two tubes (like above). One is definitely the front diff. The other one is unknown. I assume that it is either tranny or transfer case.

From what i can see, V8 4runner 4wd has only one breather tube in the engine bay. However, thanks to EXPAT, both the transmission and transfer case have short breather tubes that join together and is located at the top of the transmission.

So, short answer is that you only need to extend the rear axle breather. I would not bother with extending the other breathers...a pain-in-the-ass to do. However, you need to know the height at the top of the transmission...this is your limit in crossing water. Please do NOT listen to Toyota when they claim 27.5" of water fording capability!

 

[Expat]

As an addendum, you can find the breathers for the transfer case and transmission on the 04 V8 hiding between the firewall the inlet manifold directly above the loaction where the transmission mates to the block. You need to climb up on top of the engine to find it. With a torch you can see the white or silver valve.

By approximation, it would be only 2-3" lower than the front diff breather. You have to be in real deep to have any problems with water ingestion from these breathers. (The rear diff is another story as you all well know)

(It was a fun exercise to find those stupid breathers Thai: )

Cheers
Mark

 

[Thai]

(It was a fun exercise to find those stupid breathers Thai: )

Cheers
Mark

Thanks for your diligence, Mark! I did not know that i opened a can of worms for you!

So, now, i have to wonder...what is that extra breather tube in the V6 4runners/FJC?? Why did Toyota do this differently??

 

[Expat]

Thanks for your diligence, Mark! I did not know that i opened a can of worms for you!

So, now, i have to wonder...what is that extra breather tube in the V6 4runners/FJC?? Why did Toyota do this differently??

Next really good question!:

 

[jharris2]

V6 4runner 4wd has two tubes (like above). One is definitely the front diff. The other one is unknown. I assume that it is either tranny or transfer case.

OK, I took a look at mine tonight and traced the breathers as best as I can.

The transmission breather is also at the top of the transmission. It appears to have a plastic top to it -- it comes from the top side of the transmission and rises close to the engine. I measured it to be about 28" from ground level (18" from the breather to the rim at the top of the engine compartment, then 46" from the rim to the ground).

There appears to be another breather tube coming from the center differential, but I could not trace it. Perhaps it is one of the two that are on the right side of the engine bay (see photo above).

There is no information that I can find about it in the manuals, including the V6 supplement.

 

[Thai]

Thanks John. Hmmm, it looks like Toyota routed the transfer case breather a bit differently for the V6 and V8. Interesting.

 

[jharris2]

Thanks John. Hmmm, it looks like Toyota routed the transfer case breather a bit differently for the V6 and V8. Interesting.

And it makes no sense, either.

By the way, it looks like you could extend the transmission breather if you wanted to -- the transmission end seemed to be in a position you could get to, then re-route the hose to where you want it.

 

[mtnracer]

I would check your engine bay to confirm two breather tubes. They should look similar to these on the FJC:

http://www.toyota-4runner.org/attachment.php?s=&postid=171099

V6 4runner 4wd has two tubes (like above). One is definitely the front diff. The other one is unknown. I assume that it is either tranny or transfer case.

...

So, short answer is that you only need to extend the rear axle breather. I would not bother with extending the other breathers...a pain-in-the-ass to do. However, you need to know the height at the top of the transmission...this is your limit in crossing water. Please do NOT listen to Toyota when they claim 27.5" of water fording capability!

Why shouldn't you have water go over the top of the tranny? Also, if Toyota says that 27.5 inches is okay, why do you think this is incorrect?

 

[Thai]

Why shouldn't you have water go over the top of the tranny? Also, if Toyota says that 27.5 inches is okay, why do you think this is incorrect?

If water go over the tranny and is able to get into the breather cap, then water can enter into your tranny/TC. This is a bad thing.