M41 Transmission external oil cooler line?

Hello,

After pulling my B20 engine and M41 transmission from my 71 142e I noticed a vent line coming from the top of the M41 next to the lockout switch. After reinstalling the tranny I just put the rubber line back on that comes up into the engine compartment and goes nowhere as it was before, a vent I guessed. I am now getting a small amount of tranny fluid leaking out of the line. Apparently this is not a stock vent I have learned after searching pics of other M41s. Anybody have any idea what this is for, external oil cooler possibly?

I am just going to plug the hose for now. Here is a pic, vent has a bit of blue tape on top while it was out of the car.

Pics not working...
https://flic.kr/p/2aoRo4D

M41_OilVent by J Sandif, on Flickr

There should be a vent on the adapter housing for the overdrive. It's on the left side just under the shift rail cover.

Plug the hole in the cover. As you surmised, it doesn't belong there.

No idea why it's there unless maybe someone wanted to make it easier to add fluid without going under the car.

Thanks for confirming and yeah weird, oh well...