Tcase/Trans Breather Extension?

bugman-74

New member
I see a lot of threads on extending diff breathers, but none about transmission and/or transfer case breather extensions.

I just yanked my 5 speed (R150F+VF2A transfer I believe) and noticed there are two breather plugs. I assume one for trans and one for tcase (not sure if the auto trans is similar?). They sit fairly close to the floorboard level, which means they would be significantly lower than extended diff breathers...

Anyone extended these before? They appear to be pressed into the housing.

I have removed the caps on this style of breather plug before, and they are nothing more than a cap crimped over a flare. Awfully tempting to just yank the caps and connect some tubing of appropriate size to re-route them higher and top them off with the same breather plug used in the diff extensions (90930-03136). Anyone tried this?
 

Attachments

  • brthr.JPG
    brthr.JPG
    56.2 KB · Views: 14,607
Register to hide this ad

Those two breathers are just what they're for.

The Transfer case and the t-case adapter.

There should be another breather actually ON the transmission.

let me get with my brother and see if he can sent me a pic and I'll update.
 
For anyone else interested, stand by for a separate post with more detail on breather extension. I've seen a lot of people asking about it without many answers, so I plan to do a decent write up. I don't have my ducks in a row yet, so for now I'm just helping the OP.



First, the tranny in my Taco is a W59, so not quite the same. However, the same basics apply.

I've extended all the breathers on my Taco and 4Runner and for the most part they are very similar. Both have (had) the VF2A transfer case. The transfer case breather vents into the "dead space" between the transmission and transfer case (where they bolt together). This area should be completely empty and dry. If there is oil in here, you have one of two issues.

1 - A seal is leaking. Either the transmission output or transfer case input.
2 - The transfer case breather is putting oil there. This can happen if the transfer case is overfilled.

I prefer that the transfer case does not vent into this area.

I suppose you could pull the caps off the breathers and add hose. I've never done it that way but it seems like it should work. I always remove the breather all together. They are pressed in. Grab some pliers and start pulling/twisting. Then I use a 1/4"NPT tap to thread the hole. I do not drill the hole any larger. Just use some oil with the tap. Once that is done you can use whatever 1/4" plumbing fittings you'd like to route hose. I chose to reduce the 1/4" to 1/8" and use barbed fittings. I connect all the breathers to one main tube and route it to the driver side under the hood. It ends around the master cylinder/evap components just under the hood.

For your specific application, the transmission breather should be the one on the base of the shifter (in front of the shift lever). That's how it is on my W59 in the Taco. I don't have any pictures of that handy at the moment.
The breather at the back, driver side of the shifter is for the void between the transmission and transfer case.
I can't tell from your pic, but the transfer case shifter base has a barb on the passenger side. From what I've seen, this barb connects to a barb on the transmission by a small hose. That's how the transfer case vents into the void. It appears that yours may be capped? Again, I can't tell from the pic. The transfer case has another breather. It's the barb right above the black metal bracket on the driver side. It appears that that one is also capped on your transfer case. I cap that one as well.

Sorry for such a long answer to your question. Here's the pictures I have handy to help bring it all together. All these pictures are from my auto trans/VF2A combo.


Here's the breather for the void between the transmission and transfer case.


Here's the barb that the transfer case normally vents to on my transmission. I capped it.


Here's the transfer case shifter base with hose installed.


Here's the front breather on the auto transmission.


Here's a few pics to kind of get the idea of how they all connect and route up into the engine bay.











If that doesn't answer your question, I don't know what to tell you.
 
Last edited:
Nice work, this helps!

Indeed - there is a transmission breather (in front of the shift lever), and transfer case adapter breather (at back driver side of the shifter). The passenger side of transfer case has a barb with a ~4mm ID hose connected to the transfer case adapter. There is also a barb on the drivers side of the transfer case that is capped.

Where'd you source the constant tension hose clamps?
 
Last edited:
I have read, in several places, that all the breathers were already extended, except for the breather for the rear diff. So, we need to extend them all?
 
I have read, in several places, that all the breathers were already extended, except for the breather for the rear diff. So, we need to extend them all?

Yes.

Only exception to this is the front diff breather on some of the 4Runners.

Eevery other breather needs to be extended.
 
Indeed - there is a transmission breather (in front of the shift lever), and transfer case adapter breather (at back driver side of the shifter). The passenger side of transfer case has a barb with a ~4mm ID hose connected to the transfer case adapter. There is also a barb on the drivers side of the transfer case that is capped.

Where'd you source the constant tension hose clamps?

Seems pretty consistent with what I've seen on mine.

I got lucky when I was doing the project on my Taco and found a local hardware store that has the clamps on the shelf. Now when I need some I know exactly where to go. I order the brass barbed fittings from McMaster-Carr.
 
For anyone else interested, stand by for a separate post with more detail on breather extension. I've seen a lot of people asking about it without many answers, so I plan to do a decent write up. I don't have my ducks in a row yet, so for now I'm just helping the OP.



First, the tranny in my Taco is a W59, so not quite the same. However, the same basics apply.

I've extended all the breathers on my Taco and 4Runner and for the most part they are very similar. Both have (had) the VF2A transfer case. The transfer case breather vents into the "dead space" between the transmission and transfer case (where they bolt together). This area should be completely empty and dry. If there is oil in here, you have one of two issues.

1 - A seal is leaking. Either the transmission output or transfer case input.
2 - The transfer case breather is putting oil there. This can happen if the transfer case is overfilled.

I prefer that the transfer case does not vent into this area.

I suppose you could pull the caps off the breathers and add hose. I've never done it that way but it seems like it should work. I always remove the breather all together. They are pressed in. Grab some pliers and start pulling/twisting. Then I use a 1/4"NPT tap to thread the hole. I do not drill the hole any larger. Just use some oil with the tap. Once that is done you can use whatever 1/4" plumbing fittings you'd like to route hose. I chose to reduce the 1/4" to 1/8" and use barbed fittings. I connect all the breathers to one main tube and route it to the driver side under the hood. It ends around the master cylinder/evap components just under the hood.

For your specific application, the transmission breather should be the one on the base of the shifter (in front of the shift lever). That's how it is on my W59 in the Taco. I don't have any pictures of that handy at the moment.
The breather at the back, driver side of the shifter is for the void between the transmission and transfer case.
I can't tell from your pic, but the transfer case shifter base has a barb on the passenger side. From what I've seen, this barb connects to a barb on the transmission by a small hose. That's how the transfer case vents into the void. It appears that yours may be capped? Again, I can't tell from the pic. The transfer case has another breather. It's the barb right above the black metal bracket on the driver side. It appears that that one is also capped on your transfer case. I cap that one as well.

Sorry for such a long answer to your question. Here's the pictures I have handy to help bring it all together. All these pictures are from my auto trans/VF2A combo.


Here's the breather for the void between the transmission and transfer case.


Here's the barb that the transfer case normally vents to on my transmission. I capped it.


Here's the transfer case shifter base with hose installed.


Here's the front breather on the auto transmission.


Here's a few pics to kind of get the idea of how they all connect and route up into the engine bay.











If that doesn't answer your question, I don't know what to tell you.

really nice work, nice detail. although currently I have an automatic , I assume it has vents too.
 
Thought someone might find these pics useful - this is what I ended up doing on my 5 speed (R150F+VF2A). Long story short I extended the transmission and transfer case adapter breathers.

The OEM breathers are much easier to remove if you have the transfer case and shifter base removed (you can pop them out from the backside). FYI Both OEM breathers are true 1-way valves.

I tapped both breather holes 1/4 NPT and used 1/4 NPT right angle fittings to a 5/16 barb connection. I had to modify the right angle fitting on the transmission shifter plate so it would clear when I tightened it. I tied both fittings together with the 5/16" barb "T." I am keeping the small hose connected between the transfer case and transfer case adapter.
 

Attachments

  • IMG_7516_602x600.JPG
    IMG_7516_602x600.JPG
    82.2 KB · Views: 15,516
  • IMG_7517_800x435.JPG
    IMG_7517_800x435.JPG
    68.6 KB · Views: 9,640
  • IMG_7519_800x600.JPG
    IMG_7519_800x600.JPG
    112.1 KB · Views: 7,700
  • IMG_7523_800x513.JPG
    IMG_7523_800x513.JPG
    85.8 KB · Views: 8,435
  • IMG_7540_785x600.JPG
    IMG_7540_785x600.JPG
    108.5 KB · Views: 7,921
Wait, I could have sworn at the front diff and the transfer case had breather lines that went up into the engine bay?

Pretty sure I've seen a picture of that. Or am I crazy?
 
Wait, I could have sworn at the front diff and the transfer case had breather lines that went up into the engine bay?

Pretty sure I've seen a picture of that. Or am I crazy?
Front diff breather goes up near where the ADD VSVs mount on the bottom of the inner fender.

Visible in this pic:
D05yFg0.jpg

(right side, between the ADD VSVs and the brake line coil to the front left suspension)

Transfer case has a breather cap on the top of the adapter housing, right next to the forward shift cover.
Gx9mYrC.jpg

(also note the vacuum line to the top shift cover - it links venting between the TC and adapter housing. Electric shift TC's have an extra vacuum line that tee's in there)

Once the rear diff is handled, you can ford water up to the top of the transmission reasonably safely - though water starts getting inside, which has its own issues!

-Charlie
 
Front diff breather goes up near where the ADD VSVs mount on the bottom of the inner fender.

Visible in this pic:
D05yFg0.jpg

(right side, between the ADD VSVs and the brake line coil to the front left suspension)

Transfer case has a breather cap on the top of the adapter housing, right next to the forward shift cover.
Gx9mYrC.jpg

(also note the vacuum line to the top shift cover - it links venting between the TC and adapter housing. Electric shift TC's have an extra vacuum line that tee's in there)

Once the rear diff is handled, you can ford water up to the top of the transmission reasonably safely - though water starts getting inside, which has its own issues!

-Charlie

OH that's right. There was a member who added some breather lines right next to the front diff one. That's why I remember seeing 2 up there in a photo.
 

Members online

No members online now.

Forum statistics

Threads
278,312
Messages
3,554,083
Members
248,016
Latest member
Advally Service

Trending content

Back
Top