Leaky 727

Somewhere around 66 and earlier 727s have a 90 degree tab welded to the bottom of the tube that bolts to a tapped hole on the trans housing adjacent to where the tube goes in. They also have a tab that bolts to one of the bellhousing bolts. 67 (I think) and later only have the tab for the bellhousing bolt.

Regardless, it is important to pre fit the tube and ensure that, when the tab(s) are bolted up, the bottom of the tube isnt pre loaded. Once you have determined this, use a new o ring, wipe everything down good with lacquer thinner or brake clean (including the ID of the trans case that the tube fits into), use a reasonable (not excessive) amount of good sealant such as oil resistant rtv under and on the o ring, insert the tube and tighten the mounts. Let the sealant cure before adding oil.

This is usually something that I do as a last step, once the trans is in, the mount is on and everything is tight, to avoid tweaking the tube. I also use my finger and put a bead of sealant around the tube to trans case interface.