56 Olds Driveshaft Yoke leaking?

I thought I had seen a thread on this sometime ago, have done a search but couldn't find it.
The driveshaft yoke (Jetaway) has what looks like a frostplug in the rear of it, yet it has vent holes in it.It is leaking really bad, I have had it apart & tried to seal it with silicone whic h hasn't worked.It is leaking around the edge, not from the vent holes.
Is it OK to replace this with a standard (non vented) frost plug?
Anyone struck this before?
I need to get the car going for this weekend & can't drive it like it is.
Thanks
Russell

 

I have encountered this before on a Mazda pickup with manual transmission. But it did not have vent holes in it. The damn plug kept falling out so I had a driveshaft shop weld one in. After that no problems.

I would do the same thing with the vented plug and see what happens.