Waterproofing KZJ78 Auto Transmission.

[Henry]

Hi

After just having to rebuild the auto transmission in my KZJ78 because of water in the transmission fluid I am looking for ideas.
At the Price of a rebuild I am Really Really sure I don't want to do that again.

And yes I have a breather that is up to the top of the engine bay.

I have heard of people pressurizing the Diffs and Auto with 3 or 4 PSI.
Can someone tell me where I buy a valve like that?

I have a onboard compressor so can do that. I am a bit worried that I would forget to turn on the compressor and then create more issues. Is there a valve I can use to provide a air path to the breathers when the compressor is off. And then when I turn the compressor on this valve will close and I can pressurize the Diffs etc?

Thanks Henry

[BlakeNZ]

Henry, if you have a breather extension on it, can i ask how the water got into the transmission?

[The WEHI]

Henry, if you have a breather extension on it, can i ask how the water got into the transmission?

Most seals aren't designed to keep contaminants out they are designed to keep fluids/grease in, so prolonged submerging of seals will allow Ingres over time. Transmission clutch/friction lining uses a waterbased bonding/glue
to bond lining material to steel plates.


Ive heard of people running the cheap 12v inflatable bed style pumps and very light possitive pressure in transmissions and diffs, other then that good breathers and making sure dipsticks secure.

[kbushnz]

I take it you do a lot of river work?
As I also run that auto in my KZJ78 and have never had any issues with water...Been in plenty of mud bogs / deep water holes....Coming up 16 years now.
However I have extended the breather for the transfercase...
The Trans one is still the factory one up behind the head..

Was there a particular event that caused this?

I would imagine if the auto is hot and you plunged into cold water the sudden cooling of the trans can cause water to suck in past the seals as the air cant suck in thru the breather.... Just like the diffs do....

[tallsam66]

Id of thought easiest way for water to get in would be thru the dipstick...maybe it was partially out, or rubber seal was loose of missing.

[Big]

I take it you do a lot of river work?
As I also run that auto in my KZJ78 and have never had any issues with water...Been in plenty of mud bogs / deep water holes....However I have extended the breather for the transfercase...
The Trans one is still the factory one up behind the head..

Was there a particular event that caused this?

I would imagine if the auto is hot and you plunged into cold water the sudden cooling of the trans can cause water to suck in past the seals as the air cant suck in thru the breather.... Just like the diffs do....

Sounds interesting as I have changed to auto and haven't had any issues as of yet.. but im following this in case I need to do some pro active measures..

[Smurf]

I Tee'd my auto and transfer breathers into a common line and extended it p into the ribs in the bonnet near the hinge.

[wjw]

I Tee'd my auto and transfer breathers into a common line and extended it p into the ribs in the bonnet near the hinge.

Same here, but if you want to put air in.... I used a $5 air bed pump from katmandu, you need volume not pressure, the idea being that when in the water, it cant get in as air is coming out. I used 1" heater hose as the main line the full length of the truck. I used plastic irrigation fittings for T's, elbows etc. The only adapters I could find to go down to the breather hose size were brass. All together cost me about $80, most expensive part was the 8 meters of heater hose, although I still have a few meters left in my hose box...

[Henry]

Hi

Yes I do a bit of river work. I think that the water probably came from a Club trip in the Waimak.

I was told by the Transmission guy that he thought the water came in through the seals. I did ask if he could tell if the transmission has been repaired before. He said that main front seal was not the original. He had also seen the same water in the transmission issue before......

I do have breathers on the diffs, transmission, transfer box and front swivel hubs..

Henry

[Henry]

Hi

So I have considered a few options.

I can't leave it the way it is.....

I have discussed this with various club members. 1 has owned a KZJ78 for 14 years and his auto breather comes up to the top of the fire wall and then goes 600 mm down into the mud guard.....

I also thought about a compressor of some sort - but it would be too noisy or I would just forget to turn it on.....

I then thought about a manifold for the diffs, auto and transfer case.
I thought about venting this into the interior of the truck , but spoke to another club member who's vent dripped oil onto his wife's cloths.....
Perhaps not.....

So I thought about the same manifold into the air cleaner. I am just not sure that the turbo would not be sucking on the breather....

My other option is I have a catch can between the rocker cover and where toyota vent that into before the turbo. I thought I could connect my manifold into the catch can???
How much pressure comes out of the rocker cover?

Thoughts?????

Henry

[Big]

Don't hook it up to any positive air vacume ie on intake or the likes as all it will do is drag crap in from the seals and will just increase the chance of crap in ya tranny.. I did this on a starter motor and it was the end of the bearings because I just sucked in the crap.. I'd just say either positive pressure or leave it longer out of harms way..
My 2 cents worth..

[Henry]

Hi

I thought I would update on what I have done.

I have connected the 4 breathers from the diffs, transfer and Auto Gearbox up to a small manifold.

The output of the manifold goes to the setup in the second photo.

I then can set it up with either just a breather up to the top of the snorkel. it is the 2 taps in the second photo that I can change to a blower that is cable tied to the steering wheel column.

My thinking is that If i forget to do anything I have all sorts of other issues if I get water in the breather at the top of the snorkel.

Ideally if I am going into deep water I will change the taps and run the blower to put some pressure into the gear box etc.
Again if I have changed the taps and forget to put the blower on I still have the breather in the cab.

I hope that will help me keep water out of the gear box!!!!!