Well, I've never seen this. The last 2 times I drove this car, it dumped trans fluid after the drive, while sitting. It is leaking through the slip yoke, not around the yoke indicating a seal. What keeps fluid from slipping past the splines? I going to pull the drive shaft today and do a visual inspection. Any help?

 

Well, a search after posting revealed one other post and it explained the issue. It seems my o-ring is shot and I need to replace it or weld the vent hole closed.

 

Earlier yokes had a sort of pinhole in the middle of the steel plate at the back of the yoke to allow air to bleed out as the yoke travelled in and out of the back of the trans.
There was a seal a bit forward on the input shaft that rode in a smooth area of the yoke, before the splines started, and no oil was ever supposed to get into the area between the yoke and the end of the shaft, but that's not the way it usually worked out.

Later ones seem not to have it, but have a "missing spline" to allow air out and into the transmission when the yoke is pushed in.

Look at your yoke when it is off - if it has the "missing spline," then you can braze up the hole, grease the splines with a good grease, and all should be good.

- Eric

edit: See, you answered your own question before I could!

 

Well, what I found was a mangled rubber plug in that hole. Has anyone else seen this? I suspect a replaced plug would solve the problem for another 40 years.

 

Clean thoroughly and put a dab of RTV on the hole. Also check the tail housing bushing for wear. The yoke should not wiggle when you grab it and try to move it up and down or side to side.

 

There is such a thing as a slip yoke plug sometimes call a Welsh plug. Even found part numbers for Dana yokes.

I tired the RTV solution, we'll see.

 

Yes, but this is the large, roughly 1" diameter plug that covers the whole back and has the small hole he is talking about in the middle of it.

- Eric