Lexus GX470 Diff Breather Mods & Locations (1 Viewer)

[Bralow]

There is a lot of confusion on these breathers, here and on the FB group. So I went looking for the final answer.

According to the parts diagrams, there are a total of 4 breathers (5 depending on how you count.)

1. Rear Diff - on rear diff, no hose from factory
2. Front Diff - on front diff, hose routes to driver side engine bay, visible from above
3. Transmission - Hose runs along the top of the transmission to the bell housing
4*. Transfer Case - Hose also runs forward towards top of transmission
5** Transfer Case Actuator - Runs to #4

*You can see in the diagrams, #4 mounts with a Y-fitting, to accept the breather from the T-Case actuator
**You can see in the next picture, the actuator hose is short and only runs to the Transfer case breather Y-fitting

Rear Diff: Rear axle housing & differential for Lexus GX470 UZJ120L - Auto parts

Front Diff: Front axle housing & differential for Lexus GX470 UZJ120L - Auto parts

Transmission: Transmission case & oil pan (atm) for Lexus GX470 UZJ120L - Genuine parts

Transfer Case: Transfer case & extension housing for Lexus GX470 UZJ120L - Auto parts

NOTE: According to some parts catalogs, These breather sub-assembly PN #36407 were changed in August 2004, but the diagrams all remain the same, so YMMV:

Transfer Case Actuator: Transfer lever & shift rod for Lexus GX470 UZJ120L - Genuine parts

 

[ArBrnSnpr]

Great post!

Rear diff is a must if you live anywhere other than the Sahara.

 

[CarolinaGX]

I ran mine up along the fuel filler hose to the back side of the plastic trim where the gas cap is. I didnt see the need to cut a hole and put it through and risk splashing fuel on it when filling up.

 

[chiz45]

I ran mine up along the fuel filler hose to the back side of the plastic trim where the gas cap is. I didnt see the need to cut a hole and put it through and risk splashing fuel on it when filling up.

the only negative that i have read about this is the possibility of the fluid odor entering the cabin. Have you experienced this?

 

[GXO]

I had mine there for years. I have it down under near my aux tank now above the frame rail

 

[CarolinaGX]

No, it is not in the cabin nor is there a vent there. When you fill up for gas, there is a plastic backing plate behind the filler neck. My breather is right behind that backing plate. I used the vent cap from the axle and put it into the end of the hose.

 

[estoddart]

No, it is not in the cabin nor is there a vent there. When you fill up for gas, there is a plastic backing plate behind the filler neck. My breather is right behind that backing plate. I used the vent cap from the axle and put it into the end of the hose.

Did you replace the OEM breather valve (42110C)? How did you connect a hose there? Picture?
Thanks.

 

[CarolinaGX]

There is a Toyota part that threads into the axle housing and has a barbed fitting for the hose. I will try to find the part number and add it. Then I used fuel line and routed it up to the fuel filler. I will try to take a picture of the routing but not sure how well it will show. It is important to either leave a coil of slack to allow the axle to move in it's full range or install with the axle in full droop. Otherwise it will pull on the breather.

edit: Genuine Toyota (90404-51319) Union

 

[Commander AJ]

I just left some slack in the fuel line for articulation and tie wrapped a few loops of extra fuel line to something up close to the underside of the body. I've been meaning to plug a cheap plastic fuel filter on the open end but whatevs....it rarely gets wet here in SoCal lol!

 

[chiz45]

No, it is not in the cabin nor is there a vent there. When you fill up for gas, there is a plastic backing plate behind the filler neck. My breather is right behind that backing plate. I used the vent cap from the axle and put it into the end of the hose.

i think i'm getting this confused with the 5th gen. I routed mine in the 5th to the engine bay, but sounds like i'll be doing what you guys did in the GX.

 

[CarolinaGX]

It has been raining for days here but seems to have let up for a few. I will try to get a good picture tomorrow.

 

[estoddart]

There is a Toyota part that threads into the axle housing and has a barbed fitting for the hose. I will try to find the part number and add it. Then I used fuel line and routed it up to the fuel filler. I will try to take a picture of the routing but not sure how well it will show. It is important to either leave a coil of slack to allow the axle to move in it's full range or install with the axle in full droop. Otherwise it will pull on the breather.

edit: Genuine Toyota (90404-51319) Union

Perfect! That's exactly what I was looking for. Thanks.

 

[drowzyGX]

Extending the rear diff breather is a must. The front diff and transmission breathers look good.

is there consensus on the transfer case + transfer case actuator breathers?

Hard to tell from the diagram if they come up high enough.

 

[trinydex]

Extending the rear diff breather is a must. The front diff and transmission breathers look good.

is there consensus on the transfer case + transfer case actuator breathers?

Hard to tell from the diagram if they come up high enough.

anyone extend the transmission or transfer case breathers?

 

[CarolinaGX]

I haven't changed the tranny or the t/case

 

[LRDV8R]

I'd like to revive this discussion and get input from those that have done water crossings and their current breather set up, mainly for the transmission and transfer case. I'm most likely going to upgrade them anyway, but I'd like to hear others' experiences.

 

[Rednexus]

I do lots of water crossings, many in the 1-2 ft depth and some over 2.5', with the stock front diff, transmission, and TC case breathers and an extended rear diff breather. I change all gear oils yearly and have been in my transmission several times for various things. I have never gotten so much as a hint of water in the TC or transmission, maybe a few drops in the front diff, and a little more in the rear diff. I would leave those alone and just extend the rear diff breather. I have mine mounted next to the gas cap - honestly it was a pain to get there and required drilling a hole in the body, but it does work fine.

Either way, if you are doing frequent water crossings, I'd still change the fluid in the diffs and TC yearly. When you hit water with hot diffs it can pull in some moisture past the seals, which can slowly contaminate the fluid.

 

[LRDV8R]

I do lots of water crossings, many in the 1-2 ft depth and some over 2.5', with the stock front diff, transmission, and TC case breathers and an extended rear diff breather. I change all gear oils yearly and have been in my transmission several times for various things. I have never gotten so much as a hint of water in the TC or transmission, maybe a few drops in the front diff, and a little more in the rear diff. I would leave those alone and just extend the rear diff breather. I have mine mounted next to the gas cap - honestly it was a pain to get there and required drilling a hole in the body, but it does work fine.

Either way, if you are doing frequent water crossings, I'd still change the fluid in the diffs and TC yearly. When you hit water with hot diffs it can pull in some moisture past the seals, which can slowly contaminate the fluid.

Thanks for the response. After the money (and maybe more importantly my time) spent on the diffs, I plan to change fluids yearly. It's just too good of insurance not to.

 

[dahoseman]

I may have missed this in the thread. Forgive my ignorance. What is the benefit of a breather?

 

[LRDV8R]

Extending the breathers prevents water ingress when fording. Diffs need to breathe due to changes in internal pressure due to heat. Water contamination of the oil is bad for the diffs, tc, and trans.