Pre-war (up to 1942) 1941 Hydra-Matic Transmission Yoke

[Joe G 12138]

      RTV will not seal splines. Any oil before or after installation will work it loose and it can go places. I've had very good luck with "Rectorseal" for the last few years. This or similar stuff should be available at hardware store or plumbing supply stores. It is made for petroleum or fuel piping. The hardest part of any job is the preparation. In this case, you need to get the oil and RTV off of the spines and grooves in the yoke after they are already wet for it do do its best, but being for petroleum use it is somewhat forgiving. But the other part to be aware of is the parts that need lubrication (outer surface of yoke and actual seal surface) need a coating of grease or lubrication when assembled. It's tricky to achieve both goals at once on a "wet" installation.
      Another thing that sometimes helps with stubborn sealing is use a copper washer under the yoke bolt head. Another hardware store item; they usually have an assortment to pick through. I guess I picked that up from working on the German cars....They love copper washers and "O" rings!

[Daryl Chesterman]

I noticed in this picture from post #26, that the end of the splined shaft looks like someone has beat on it with a hammer or something else, thus there is not a smooth sealing surface for the inside of the yoke to seal against.

https://forums.cadillaclasalle.club/index.php?action=dlattach;fs=73948;attach=215659

You might want to examine the inside end of the splined yoke to be sure that surface has no foreign material.  Since the lip of the seal on the outside of the yoke seals that surface, the only other place for a leak is where the inside end of the yoke seats against the end of the splined shaft.  When reassembling, I would place a small bead of ATF resistant sealer on the end of the shaft, lubricate the lip of the housing seal and the corresponding surface of the yoke, then install the yoke and torque the bolt to specs.

Daryl Chesterman