Newbie question - hole in transmission?

[Goliath]

Spending more time under my truck I noticed a threaded hole near the front of the transmission. Searching around some on the internet, I learned it's not a sealed part of the tranny and hole is supposed to be there so no panic, but just wondering the actual purpose.

 

[MOBS]

What tranny is it? Just a wild guess, but possibly a vent hole for a tube to hook to for when tranny gets hot?!

 

[jdyates]

Just went to look out of curiosity and sure enough mine has it too. I have the 700R4. Maybe you screw a hose into it to flush old tranny fluid somehow?

 

[Goliath]

Mine is a 4L80E, I read somewhere that it's to know when the seals were leaking but I'm pretty sure that was a dig.

 

[Luke(MI)]

probably a vent hole.

 

[Goliath]

Well after a few minutes of thinking a plug came out and I have been running without fluid, I checked the fluid level and it was fine then web check found a few people mention GM been putting the holes there for a long time - I just really wanted to make sure it isn't something I am supposed to service somehow.

 

[FastOrange]

Is it the hole that is on top of the case on the drivers side, in this pic?

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[k_pro1992]

Is it the hole that is on top of the case on the drivers side, in this pic?

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i think he's talking about the one on the bottom front passengers side.

 

[Goliath]

Here's a pic (it's more on the driver's side and almost all the way up to the oilpan.) I think you can see it in the pic.

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Doesn't sound like a big deal so I'm not going to worry about it, just trying to learn as I go.

 

[Southern Pride]

Aha! I've seen this on mine as well...That's all I have to add for your knowledge but this does make me feel alot better.