Help needed! Trans breather blowing fluid out

Alright fellas, here’s the deal. I just finished the IPT transmission valve body upgrade. ( before I go on I must say that the John at IPT has been nothing but fantastic with his customer support, I do NOT blame them Them for this at all! ) After the first install I noticed transmission fluid leaking, I followed it up and it’s coming from the trans breather line. It only blows fluid out after a long sit time, 24hrs, and sometimes after engine shut off. When it blows out it will happen for about 3-10 seconds then stop. Maybe a 1/10 of qt at a time but enough to notice a puddle under the truck.

I talked to John at IPT he said that I might have put a part in upside down( that part being a metal ball held by a black plastic holder with a spring ). After this conversation I took it back apart and reassembled it. While taking the valve body off the part fell out before I could see if it was installed incorrectly. This time around it is most definitely put back on correctly. After this second reassembly it happened to me again when I started the truck . After letting the transmission get to correct temp 115-130f I checked the fluid level and it was spot on, additionally the the fluid level was spot on the first time around.

I have to let the truck sit for another 24 hours before giving it another try to see if it’s still blowing fluid, I will update this tomorrow and the following days.

Does anyone have any ideas of what could be going on?

pics below:
It’s hard to see but you can see red fluid coming out from the breather line. It’s circled in red. The other pic is of the part that might have been out in up side down.

 

@gearcruncher

If anyone knows, this guy would be the one. Maybe he will see this pretty quick.

 

I’m assuming when you say the fluid level is spot on Now and was spot on the first time that you added more fluid the second time than what came out.

 

That is correct, after the second removal I returned what drained out and eye balled about another QT to make up for what’s been coming out of the breather.

 

The issue is related to the Anti-drain back valve .
The anti drain back valve prevents your transmission fluid from draining out of the torque converter and back into the transmission pan when you shut your truck off .
Why is the anti drain back valve needed ?
If your transmission pump had to fill your torque converter every time you started your truck , it would take a while for your truck to begin moving and we as Tacoma owners just wont stand for any delays .

Let me do some digging in my manuals . I may have a fix for you

1 thing that would be good to know ? Does IPT change anything in the valve body to effect the drain back circuit ?

 

Sweet!!! Thank you!! I have no idea what they acutely do to that thing, far as I know they could sprinkle some leprechaun magic in there. I’ll give them a call and see what they think.

 

Just got off the phone with John from IPT. They don’t do anything to the drain back circuit.

 

@gearcruncher

not to rush you and I’m very thankful for any help you can provide but I’m waiting to hear back from you otherwise I’m going to pull the valve body off and send it back to IPT. I would much rather see what you got to say before paying another $200 for shipping.

 

Until you hear back from him, you might read this on the A7 series.
It’s got a lot of good information in it, it doesn’t mention that drain back valve.
But it does give some good information on things to look for when working.

https://atracom.blob.core.windows.net/webinars/import/toyotaa750_a761_introduction.pdf

 

Thank you, tnshooter , I’ve already watched that video twice now to try and find something. Definitely some good information in it.

 

It’s not a video???
It should be a pdf?

 

Yup you right... I thought that was the video webinar going over the transmission. Just finished looking through it. Still .... great information. 1 thing I did notice is that it said the truck should be level when being filled back with tranny fluid. I’m wondering how critical this might be ? When I filled the tranny back up it was in my drive way with a slight incline. Nothing crazy .

 

I honestly don’t know, but wouldn’t think a slight incline would cause enough of an over fill to cause it to blow out vent.

I do remember one case that “claimed to be an over fill” and leaked from the vent.
But I think it would have to be way over filled?


https://www.tacomaworld.com/threads/leaked-transmission-fluid-concern.671636/page-2#post-23590028

 

So it got filled at slight incline then checked at level ground.

 

If it checked out on level ground all should be good.

How exactly is it you are checking the fluid level?

 

Are you doing it as described in this link?

https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

 

First level ground, second allowing trans pan temp checked by scan gauge to get to 115-130, third while truck is running pulling “level bolt” - one with Allen wrench and seeing a “trickle” wtf ever that means. Fourth putting said Allen bolt back in.

 

Re-reading the title of the post... man, too easy.

 

hahah ya trust me I know. I had a few giggles myself. Figured it would catch the eye of everyone.

 

Your issue deals with the anti drain back valve not performing as it should operate .
This issue is not a common problem with the A750 Series transmission and this makes your problem very difficult to diagnose over a keyboard considering a valve body was just installed and you never had a vent leak before the IPT valve body was installed
I would suggest using the technicians assistance at IPT try and help you out , rather than removing the valve body again .
Those guys have a multitude of employees .Mondays and Fridays come into effect . 1 missing check ball in that valve body is all it would take to create a problem such as yours .
Do they check the drain back circuit during a valve body shift test ?
Considering you already had the valve body off a couple times , its time to let the boys at IPT try the valve body on a good working A750 series transmission for verification of proper function