Rear Diff Breather Mod

[RunnerLimited]

With the way I ran mine, I don't think it would ever come close to the exhaust. But, I used a lot of zip ties to hold it in place where I wanted. I have an extra loop of slack for axle articulation and in the case I drop the axle down to replace springs, but even with that extra loop, it won't come near the exhaust. Maybe take a look at the video I made to see how I ran mine.

Yeah ill check it out, the mod is easy enough just sucks having to do it in winter months if it keeps happening

 

[Clayton74]

If your gas cap isnt high enough then you may want to check your front diff and transmission. Both of those breather valves are lower than your gas cap.

I've been having issues with my T-case more than than anything. Had to drain water out a few times now. Need to get under the center console and re-route that. Does the auto trans have a breather other than the dipstick?

 

[mtbtim]

I've been having issues with my T-case more than than anything. Had to drain water out a few times now. Need to get under the center console and re-route that. Does the auto trans have a breather other than the dipstick?

You're comment is thought provoking. The rear differential extended breather mod is well-documented but there doesn't seem to be much talk regarding sucking water into the transfer case or transmission. If you're going deep enough to submerge your differential, you're very close to submerging your trans and transfer case too.

I'm pretty sure there's got to be a breather somewhere on the top of our automatic transmissions. Has anyone rerouted their transfer case and auto trans breathers? If so, where did you reroute to and could you share some pics of how you did it?

 

[Myrunr2010]

You're comment is thought provoking. The rear differential extended breather mod is well-documented but there doesn't seem to be much talk regarding sucking water into the transfer case or transmission. If you're going deep enough to submerge your differential, you're very close to submerging your trans and transfer case too.

I'm pretty sure there's got to be a breather somewhere on the top of our automatic transmissions. Has anyone rerouted their transfer case and auto trans breathers? If so, where did you reroute to and could you share some pics of how you did it?

My manual trans does, but I would guess that an automatic does not except for the dip stick, but that's a guess. The transmission breather is on the very top of the trans, and your front diff breather is just below your battery tray.

My point wasn't that those need to be extended (although perhaps Clayton does), my point was that the gas filler cap is plenty high enough to extend it.

 

[Clayton74]

You're comment is thought provoking. The rear differential extended breather mod is well-documented but there doesn't seem to be much talk regarding sucking water into the transfer case or transmission. If you're going deep enough to submerge your differential, you're very close to submerging your trans and transfer case too.

I'm pretty sure there's got to be a breather somewhere on the top of our automatic transmissions. Has anyone rerouted their transfer case and auto trans breathers? If so, where did you reroute to and could you share some pics of how you did it?

I've definitely located my T case breather. You have to pull up the center console and unbolt the boot to get to it. It's just a short metal stub out of the top of the case if I remember correctly. I should have routed it to my dash when I was upgrading to a console with cup holders. Since my rig is predominately off road and we have a lot of rivers in AK, it's not uncommon to have water come over my hood at least briefly or 1/2 way up the doors (had it to the bottom of my window before) as you cross across the current. The breather on the T case actually sits pretty low when you really get in and look at it.

I've snorkeled the intake, relocated the rear up inside the rear hatch pillar and extended the front diff. I always assumed the auto trans would be OK because I don't spend a lot of time in the water (in and out) and the dip stick seals pretty well. If there is another breather, I definitely need to address it.

 

[mtbtim]

My manual trans does, but I would guess that an automatic does not except for the dip stick, but that's a guess. The transmission breather is on the very top of the trans, and your front diff breather is just below your battery tray.

My point wasn't that those need to be extended (although perhaps Clayton does), my point was that the gas filler cap is plenty high enough to extend it.

I totally understood what you were getting at but [MENTION=130208]Clayton74[/MENTION] comment got me thinking. What's the point of extending the breather on your rear differential if you just going to end up sucking water into your transfer case and transmission? Your differential is good but you water log your trans and transfer case. Just sounds like an incomplete modification. If you're doing this to be able to ford creek or river crossings without damaging anything, we're coming up short with only the rear diff breather extended.

Doing the trans and transfer case though doesn't look so easy unless you drop them. The breathers are on top and are probably hard to get to. Also, I saw one thread showing how one guy did it by pulling the old breathers out, which are press fitted into the housing, tapping the hole, and then screwing in fittings. To do it like this guy did, the trans and transfer case were out of the rig. Here's the thread:

http://www.toyota-4runner.org/3rd-gen-t4rs/202406-tcase-trans-breather-extension.html

I know for sure I wouldn't drop the transmission and transfer case just to do this, so unless somebody has an easier way to do it, I think I'll leave well enough alone and hope the stock breathers keep the water out if I ever go through a deep crossing. The rear differential breather does have a spring valve, and if the trans and transfer case breathers are the same design, very little water if any is going to get in if the valve isn't compromised. But, if that spring valve gets stuck open, then you're kind of screwed if you go into deep water. The chance of the valve sticking open is the reason why I decided to do the rear diff breather mod in the first place.

 

[mtbtim]

I've snorkeled the intake, relocated the rear up inside the rear hatch pillar and extended the front diff. I always assumed the auto trans would be OK because I don't spend a lot of time in the water (in and out) and the dip stick seals pretty well. If there is another breather, I definitely need to address it.

Look at that thread link I provided in the previous post. There's definitely a couple breathers on top of our auto transmissions. If you end up extending the transfer case breather and trans breathers, please share with us how you did it.

 

[Myrunr2010]

Tapping a hole on top of your trans sounds like a quick way to fill that sucker up with metal shavings and cause bigger issues than having to worry about water.

 

[mtbtim]

Tapping a hole on top of your trans sounds like a quick way to fill that sucker up with metal shavings and cause bigger issues than having to worry about water.

I was thinking the same thing.

 

[Roc Doc]

I just used the bellows style. No hoses to mess with, or gear oil smell in the cab.

 

[mtbtim]

I just used the bellows style. No hoses to mess with, or gear oil smell in the cab.

Care to expand on this? How does the bellows style work? Could you share a pic of what it looks like on your rig?

 

[Roc Doc]

Care to expand on this? How does the bellows style work? Could you share a pic of what it looks like on your rig?

You take the factory breather out of the axle housing and replace it with the barbed brass fitting, put the bellows on the barbed fitting and use the hose clamp. The system is now sealed against water, but as the housing heats and cools the bellows expands or contracts to accommodate the change in PSI.


Here's one installed on the Dana 60 of my old buggy.

 

[mtbtim]

You take the factory breather out of the axle housing and replace it with the barbed brass fitting, put the bellows on the barbed fitting and use the hose clamp. The system is now sealed against water, but as the housing heats and cools the bellows expands or contracts to accommodate the change in PSI.


Here's one installed on the Dana 60 of my old buggy.

Got it and I guess I should have been able to figure that out on my own. I like this idea. But, I wonder how much pressure can build up in the differential and if the bellow can handle it. What if you go on a very long drive? Will that thing continue to expand until it pops like a balloon?

 

[fourfive]

...What's the point of extending the breather on your rear differential if you just going to end up sucking water into your transfer case and transmission? Your differential is good but you water log your trans and transfer case...

The rear differential breather does have a spring valve, and if the trans and transfer case breathers are the same design, very little water if any is going to get in if the valve isn't compromised. But, if that spring valve gets stuck open, then you're kind of screwed if you go into deep water. The chance of the valve sticking open is the reason why I decided to do the rear diff breather mod in the first place.

I saw you mention the spring valve in the breather in your video & was thinking if just changing out the breather with a new toyota breather every so often to avoid the possibility of the spring valve going bad would be an alternative?

 

[Sean K.]

I totally understood what you were getting at but [MENTION=130208]Clayton74[/MENTION] comment got me thinking. What's the point of extending the breather on your rear differential if you just going to end up sucking water into your transfer case and transmission? Your differential is good but you water log your trans and transfer case. Just sounds like an incomplete modification. If you're doing this to be able to ford creek or river crossings without damaging anything, we're coming up short with only the rear diff breather extended.

Doing the trans and transfer case though doesn't look so easy unless you drop them. The breathers are on top and are probably hard to get to. Also, I saw one thread showing how one guy did it by pulling the old breathers out, which are press fitted into the housing, tapping the hole, and then screwing in fittings. To do it like this guy did, the trans and transfer case were out of the rig. Here's the thread:

http://www.toyota-4runner.org/3rd-gen-t4rs/202406-tcase-trans-breather-extension.html

I know for sure I wouldn't drop the transmission and transfer case just to do this, so unless somebody has an easier way to do it, I think I'll leave well enough alone and hope the stock breathers keep the water out if I ever go through a deep crossing. The rear differential breather does have a spring valve, and if the trans and transfer case breathers are the same design, very little water if any is going to get in if the valve isn't compromised. But, if that spring valve gets stuck open, then you're kind of screwed if you go into deep water. The chance of the valve sticking open is the reason why I decided to do the rear diff breather mod in the first place.

How well sealed is the shifter hole in the 3rd Gen tcase? In gear driven cases, they breath through the shifter hole....unless the new ones are really well sealed, extending the breather may not do much good.

Basically what it boils down to is: if you do a lot of deep water crossings, you need to change your fluids afterwards. Most guys here in AZ that wheel the harder trails where water is well over 40" tires run the cheapest gear oil they can rather than Redline, Amsoil, Royal Purple, etc.....b/c they know they're just going to have to change it after one trail.

 

[mtbtim]

I think it's definitely a viable alternative, but you just don't know when something like that will fail. I think it's more something that could happen to people who live in the rust belt of the country. When I replaced my original 14 yr old breather a couple years ago, it was still functional. The benefit of the extended breather is you don't have to worry about whether or not that little spring valve is working properly when you drive through moderately deep water. But since I was ignorant of the fact that breathers on the trans and transfer case aren't extended, I'm now wondering what's the point.

Sent from my XT1060 using Tapatalk

 

[Clayton74]

I totally understood what you were getting at but [MENTION=130208]Clayton74[/MENTION] comment got me thinking. What's the point of extending the breather on your rear differential if you just going to end up sucking water into your transfer case and transmission? Your differential is good but you water log your trans and transfer case. Just sounds like an incomplete modification. If you're doing this to be able to ford creek or river crossings without damaging anything, we're coming up short with only the rear diff breather extended.

Doing the trans and transfer case though doesn't look so easy unless you drop them. The breathers are on top and are probably hard to get to. Also, I saw one thread showing how one guy did it by pulling the old breathers out, which are press fitted into the housing, tapping the hole, and then screwing in fittings. To do it like this guy did, the trans and transfer case were out of the rig. Here's the thread:

http://www.toyota-4runner.org/3rd-gen-t4rs/202406-tcase-trans-breather-extension.html

I know for sure I wouldn't drop the transmission and transfer case just to do this, so unless somebody has an easier way to do it, I think I'll leave well enough alone and hope the stock breathers keep the water out if I ever go through a deep crossing. The rear differential breather does have a spring valve, and if the trans and transfer case breathers are the same design, very little water if any is going to get in if the valve isn't compromised. But, if that spring valve gets stuck open, then you're kind of screwed if you go into deep water. The chance of the valve sticking open is the reason why I decided to do the rear diff breather mod in the first place.

I'll definitely take some pictures. No question my mods weren't complete, but a guy has got to get out and hunt when the season is going on! I've seen the T case, and it's no big deal to extend, I'm going to have to look harder at the auto trans. It's on my to do list this winter along with repairing a couple wires on the top of my T case that got ripped off while driving through 10-12' alders. I kind of took a fix the easiest stuff first approach. I started with the rear diff then added a snorkle and extended the front diff. I need to circle back and pick up the rest of my cases.

 

[Roc Doc]

Got it and I guess I should have been able to figure that out on my own. I like this idea. But, I wonder how much pressure can build up in the differential and if the bellow can handle it. What if you go on a very long drive? Will that thing continue to expand until it pops like a balloon?

They use them on Ultra 4 cars in racing conditions. You might be over/under thinking this. :cheers:

 

[TheDurk]

The rear breather happens to sit between two wheels and lives in a nasty bath of salty road splash all winter here in NJ. On the other hand, I checked my trans and TC breathers when I did my clutch renew three years ago and they were pristine. They are very well protected up top there and far from all four wheels. I don't do deep water so I'm not worried about them as they are. On the other hand, my rear was rusted solid as I discovered while I just had the diff off.

 

[Inoahguy]

http://www.toyota-4runner.org/3rd-g...erential-breather-valve-pressure-buildup.html

I ran mine up under the hood (drivers side wheel well)

I'd have some concerns about gear oil odors inside the cab when running it into the interior.

I had the same concern. However my cousin did it on his '97 and hasn't had a problem in a couple of years.