Front Diff, Transfer Case, and Auto Transmission Breathers

All the metal caps on my truck were 1ways. I took them off and confirmed. Couldn't blow out of them. Front diff, rear, transfer

 

That is very interesting. You would think they would vent air out but not in.

 

Yes I believe that is what they should be, maybe just a description issue? They probably designed it that way to keep things clean vs atmospheric breathers especially with the long fluid change intervals. Shouldn't have the issue that the rear diff has since they aren't as low. Some people have had moisture issues with the ADD but I bet a lot of them are from broken or disconnected breather lines or poor sealing.

 

The dorman replacements metal caps are true in and out .

 

Its designed to be used in the event of a water crossing. Most rivers are significantly colder than ambient temp causing a rapid cooling of the casing results in an intake of air due to the temp change. I believe it should breath in and out as its name suggests but toyota might have wanted it to keep pressure for fluid longevity, either way I think it contributed to my leak.

 

I just hunted down my silver T case breather ends, removed them and tested them. when I removed the breather on the T case (not actuator) i got positive pressure, air releasing on the hose coming from the T case. sounded like an almost empty bike tube deflating for about 5 seconds. there was some positive pressure in there that the breather was not letting out is that normal? truck has not been used for a few days. Upon testing my breather, it is designed to air escape from the T case but will not let any air into the t case and it does seem to be testing fine which is odd since I had positive pressure. It is spring loaded however so perhaps the spring got weak and the blocking device sags down and will not let the pressure release out of the t case when its faced upright the way its mounted. not sure if its designed to have some amount of pressure in the T case and at a certain amount it releases/vents? anyway, I'm going to look for a replacement breather now. any tips on a true two way thats not as expensive as the arb unit?

 

i got the 30 dollar alternative to the ARB unit on Amazon and it works great. Bought 2 of them

 

this unit?

$46 Differential Axle Breather Replacement for ARB 170112 Kit Compatible with Drivetrain Assemblies, Differentials, Transmission and Transfer Case of 4×4 4WD Accessories

https://www.amazon.com/dp/B07V3C77HY

 

very similar except mine didnt have any text on the filter head.

 

Vacuum pressure does seem more likely although the one way breathers will require a certain amount of pressure to open so will hold some amount of pressure. It is possible that they intend for it to hold a bit and use a stiffer spring to achieve that as well. It would actually help prevent a vacuum forming when things cool.

 

Sorry to bring up this dead post, but are those 2 breathers by the driver side battery case both specifically for the front differential only or is 1 for the front diff and the other is for the transmission?

 

Both transfer case breathers are on the firewall. I believe the 2 on the driver side are the front diff

 

I am moving my rear diff breather up into my taillight. What I am looking for is information on moving my transfer case breather. I have a 2020 manual and was told the transer case breather is on top of the case. Last fluid change I found some water in the fluid, looking to keep that from happening again. Anyone have seen or done this kind of mod?

 

Yes a few have done it including myself.

 

Do you have any suggestions, sample of a process? Am I correct that the breather is on the top of the case? Is there a thread on here that I am missing?

 

auskip07 - Skip, I went back through your threads and read all of your transfer case issues. I originally skipped it thinking it had more to do with your leaking problem. I am still confused as I cannot find anything on the manual transmission but see where the automatics have the breather piped up into the engine bay. Hence my confusion on where my breather is located - I have not been in any water crossings over my wheel wells so how did the water get into my case? The mechanic I talked to told me the breather is just like the rear diff - on top of the case???

 

Without a manual transmission I can't say for certain. It's on top of the bell housing. Follow it from below all the way until you run out of arm. Then I just yanked it off the mount because I wanted to replace the check valve.

 

Thank you, there isn't the two silver caps in my engine bay so I am going to assume the transfer case is as the mechanic shared with me and buy the same materials I secured for the rear diff transition - just in case. Then I will remove the skid plates and see what's up with the front diff. Thank you again, I hope your chalenge with Toyota gets resolved for you.

 

So far after cleaning, fluid change and sealing all the bolts under the fill bolt it's slowed down to my liking

 

That's good but it still shouldn't have happened nor you get the run-a-round by Toyota. No one stands behind thier warranties any more. I had an issue with my new Fox Shocks when I lifted my truck. One of the rear shocks was leaking, called Fox and had to jump through a bunch of hoops only to find they weren't going to stand by their warranty. I had a shock service shop in Denver rebuild them - they shared the bushings were installed backwards from the factory (not the first time they have seen this). Everything is working as it should now but I had to pay for a repair that was a factory defect. Go figure