Mine had leaked down so that no more would run out. If I'd kept the car, I'd have swapped the tube for a FitzAll stick & tube, with the top hat type seal. My tranny guy told me about 'em. Says he has sold a lot of 'em. Says top hat seal works MUCH better than the single O-ring.
Or, if you wanna keep your stock tube, you can cut off the end & attach one of the top hat seal type repair ends. I think Cliff has mentioned using these. These parts are sold on Ebay, Amazon and probably lots of trans shops.
http://www.fitzall.com/filler_tubes.php
https://www.amazon.com/Universal-Aut.../dp/B00B40MPVM
http://www.ebay.com/itm/TH350-TH350C...ZRlSCr&vxp=mtr
http://www.ebay.com/itm/Filler-Tube-...JWp9SE&vxp=mtr
http://www.ebay.com/itm/Dipstick-Fil...-/300803616743