Transmission Breather: Replace or Clean?

Hello All

got another issue for your consideration.

My truck:

1998 4x4 V6 3.4L manual trans

My transmission is slowly leaking gear oil from the 4x4 shift lever plate. Someone suggested that the problem could be clogged breathers causing pressure to build up and seek escape elsewhere.

three questions:

1) Does that sound plausible?

2) if yes, should I try cleaning the breathers, or just go ahead and replace them? for whatever answer you give: why?

3) If I should replace them, how do I go about doing that? Unlike differential breather, there doesnt appear to be a hex to grab on to...

Oh, and another thing, a mechanic tried to quick fix the leak by sealing with a copious amount of RTV. I read elsewhere that thats not a great idea for the shift lever plate. Any thoughts there?

Thanks all!

 

Breathers for the most part dont wear out but they can plug up . A quick blast of air or a small screwdriver to clean them out works good .
Are you sure your oil level is proper ?
http://www.customtacos.com/tech.old...6toyrm/06toypdf/06rmsrc/rm2006ta/03100410.pdf



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Hey gearcruncher!

So I went ahead and cleaned the transmission breathers as you suggested. I also cleaned the rear and front diff breathers cuz they were looking funky as hell.

The front diff breather looked like it had somehow spewed oil out. There was thick gunk built up all along the hose, I guess from where oil dripped down (I feel foolish for not noticing that earlier). Do you know what would have caused it to spew like that?? Or maybe the previous owner just accidentally spilled some engine oil down there when doing an oil change?

Thanks for the reply!

 

Most likely its just a mix of road grime, dust and any volatile vapors coming from the breather.

 

Hmmmm. Maybe. But it's wet, glistening, and smells like gear oil, and it's only on the breather hose and all the stuff below the breather, not above or to the side...

 

Checking the oil level will give you the answers . Some guys dont wait for the oil to stop dripping when they service the diffs / transmission / transfer case etc etc .
If oil is coming out the vent , chances are the component was overfilled or there is an issue with heat . Everything expands as it heats up .
In your case , I would double check the fluid level in the transfer case and your front diff .
Look into the breather modifications if you plan to play in the mud

 

So I checked the oil levels in my front and rear diff. Both came pouring out as soon as I opened the filler plugs! I let them drain from the fill plug, but I have read that even that level is too high. Should I drain them some more, from the drain plug? How do I know when to stop?

Good news is the oil looked brand new. The seller told me he had just had them done, now I believe him!

As far as the transmission is concerned, I had the dealer look at those leaks last weekend, and in the process they told me then that the oil level is fine.

 

Here is the FSM for adjusting your fluid level . It may not be for your exact truck , however , it shows you how to properly adjust the fluid .
http://www.customtacos.com/tech.old...6toyrm/06toypdf/06rmsrc/rm2006ta/03700210.pdf